Python314/Doc/html/reference/lexical_analysis.html - master - shapovalovav/AI-Agent

Python314/Doc/html/reference/lexical_analysis.html
1 775 строк152 KB
Anatoly1147
first_commit
11 июл 2026, 17:02
11 июл 2026, 17:02f6c78bd
<!DOCTYPE html>

<html lang="en" data-content_root="../">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="viewport" content="width=device-width, initial-scale=1" />
<meta property="og:title" content="2. Lexical analysis" />
<meta property="og:type" content="website" />
<meta property="og:url" content="https://docs.python.org/3/reference/lexical_analysis.html" />
<meta property="og:site_name" content="Python documentation" />
<meta property="og:description" content="A Python program is read by a parser. Input to the parser is a stream of tokens, generated by the lexical analyzer(also known as the tokenizer). This chapter describes how the lexical analyzer prod..." />
<meta property="og:image" content="_static/og-image.png" />
<meta property="og:image:alt" content="Python documentation" />
<meta name="description" content="A Python program is read by a parser. Input to the parser is a stream of tokens, generated by the lexical analyzer(also known as the tokenizer). This chapter describes how the lexical analyzer prod..." />
<meta name="theme-color" content="#3776ab">
<meta property="og:image:width" content="200">
<meta property="og:image:height" content="200">

    <title>2. Lexical analysis &#8212; Python 3.14.4 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
    
    <link rel="stylesheet" type="text/css" href="../_static/pygments.css?v=b86133f3" />
    <link rel="stylesheet" type="text/css" href="../_static/classic.css?v=234b1a7c" />
    <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?v=82640b3f" />
    <link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css?v=5349f25f" />
    
    <script src="../_static/documentation_options.js?v=1885ab2e"></script>
    <script src="../_static/doctools.js?v=9bcbadda"></script>
    <script src="../_static/sphinx_highlight.js?v=dc90522c"></script>
    
    <script src="../_static/sidebar.js"></script>
    
    <link rel="search" type="application/opensearchdescription+xml"
          title="Search within Python 3.14.4 documentation"
          href="../_static/opensearch.xml"/>
    <link rel="author" title="About these documents" href="../about.html" />
    <link rel="index" title="Index" href="../genindex.html" />
    <link rel="search" title="Search" href="../search.html" />
    <link rel="copyright" title="Copyright" href="../copyright.html" />
    <link rel="next" title="3. Data model" href="datamodel.html" />
    <link rel="prev" title="1. Introduction" href="introduction.html" />
    
      
      <link rel="canonical" href="https://docs.python.org/3/reference/lexical_analysis.html">
      
    

    
    <style>
      @media only screen {
        table.full-width-table {
            width: 100%;
        }
      }
    </style>
<link rel="stylesheet" href="../_static/pydoctheme_dark.css" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css">
    <link rel="shortcut icon" type="image/png" href="../_static/py.svg">
            <script type="text/javascript" src="../_static/copybutton.js"></script>
            <script type="text/javascript" src="../_static/menu.js"></script>
            <script type="text/javascript" src="../_static/search-focus.js"></script>
            <script type="text/javascript" src="../_static/themetoggle.js"></script> 
            <script type="text/javascript" src="../_static/rtd_switcher.js"></script>
            <meta name="readthedocs-addons-api-version" content="1">

  </head>
<body>
<div class="mobile-nav">
    <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
           aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu">
    <nav class="nav-content" role="navigation">
        <label for="menuToggler" class="toggler__label">
            <span></span>
        </label>
        <span class="nav-items-wrapper">
            <a href="https://www.python.org/" class="nav-logo">
                <img src="../_static/py.svg" alt="Python logo">
            </a>
            <span class="version_switcher_placeholder"></span>
            <form role="search" class="search" action="../search.html" method="get">
                <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
                    <path fill-rule="nonzero" fill="currentColor" d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"></path>
                </svg>
                <input placeholder="Quick search" aria-label="Quick search" type="search" name="q">
                <input type="submit" value="Go">
            </form>
        </span>
    </nav>
    <div class="menu-wrapper">
        <nav class="menu" role="navigation" aria-label="main navigation">
            <div class="language_switcher_placeholder"></div>
            
<label class="theme-selector-label">
    Theme
    <select class="theme-selector" oninput="activateTheme(this.value)">
        <option value="auto" selected>Auto</option>
        <option value="light">Light</option>
        <option value="dark">Dark</option>
    </select>
</label>
  <div>
    <h3><a href="../contents.html">Table of Contents</a></h3>
    <ul>
<li><a class="reference internal" href="#">2. Lexical analysis</a><ul>
<li><a class="reference internal" href="#line-structure">2.1. Line structure</a><ul>
<li><a class="reference internal" href="#logical-lines">2.1.1. Logical lines</a></li>
<li><a class="reference internal" href="#physical-lines">2.1.2. Physical lines</a></li>
<li><a class="reference internal" href="#comments">2.1.3. Comments</a></li>
<li><a class="reference internal" href="#encoding-declarations">2.1.4. Encoding declarations</a></li>
<li><a class="reference internal" href="#explicit-line-joining">2.1.5. Explicit line joining</a></li>
<li><a class="reference internal" href="#implicit-line-joining">2.1.6. Implicit line joining</a></li>
<li><a class="reference internal" href="#blank-lines">2.1.7. Blank lines</a></li>
<li><a class="reference internal" href="#indentation">2.1.8. Indentation</a></li>
<li><a class="reference internal" href="#whitespace-between-tokens">2.1.9. Whitespace between tokens</a></li>
<li><a class="reference internal" href="#end-marker">2.1.10. End marker</a></li>
</ul>
</li>
<li><a class="reference internal" href="#other-tokens">2.2. Other tokens</a></li>
<li><a class="reference internal" href="#names-identifiers-and-keywords">2.3. Names (identifiers and keywords)</a><ul>
<li><a class="reference internal" href="#keywords">2.3.1. Keywords</a></li>
<li><a class="reference internal" href="#soft-keywords">2.3.2. Soft Keywords</a></li>
<li><a class="reference internal" href="#reserved-classes-of-identifiers">2.3.3. Reserved classes of identifiers</a></li>
<li><a class="reference internal" href="#non-ascii-characters-in-names">2.3.4. Non-ASCII characters in names</a></li>
</ul>
</li>
<li><a class="reference internal" href="#literals">2.4. Literals</a></li>
<li><a class="reference internal" href="#string-and-bytes-literals">2.5. String and Bytes literals</a><ul>
<li><a class="reference internal" href="#triple-quoted-strings">2.5.1. Triple-quoted strings</a></li>
<li><a class="reference internal" href="#string-prefixes">2.5.2. String prefixes</a></li>
<li><a class="reference internal" href="#formal-grammar">2.5.3. Formal grammar</a></li>
<li><a class="reference internal" href="#escape-sequences">2.5.4. Escape sequences</a><ul>
<li><a class="reference internal" href="#ignored-end-of-line">2.5.4.1. Ignored end of line</a></li>
<li><a class="reference internal" href="#escaped-characters">2.5.4.2. Escaped characters</a></li>
<li><a class="reference internal" href="#octal-character">2.5.4.3. Octal character</a></li>
<li><a class="reference internal" href="#hexadecimal-character">2.5.4.4. Hexadecimal character</a></li>
<li><a class="reference internal" href="#named-unicode-character">2.5.4.5. Named Unicode character</a></li>
<li><a class="reference internal" href="#hexadecimal-unicode-characters">2.5.4.6. Hexadecimal Unicode characters</a></li>
<li><a class="reference internal" href="#unrecognized-escape-sequences">2.5.4.7. Unrecognized escape sequences</a></li>
</ul>
</li>
<li><a class="reference internal" href="#bytes-literals">2.5.5. Bytes literals</a></li>
<li><a class="reference internal" href="#raw-string-literals">2.5.6. Raw string literals</a></li>
<li><a class="reference internal" href="#formatted-string-literals">2.5.7. f-strings</a></li>
<li><a class="reference internal" href="#template-string-literals">2.5.8. t-strings</a></li>
<li><a class="reference internal" href="#formal-grammar-for-f-strings">2.5.9. Formal grammar for f-strings</a></li>
</ul>
</li>
<li><a class="reference internal" href="#numeric-literals">2.6. Numeric literals</a><ul>
<li><a class="reference internal" href="#integer-literals">2.6.1. Integer literals</a></li>
<li><a class="reference internal" href="#floating-point-literals">2.6.2. Floating-point literals</a></li>
<li><a class="reference internal" href="#imaginary-literals">2.6.3. Imaginary literals</a></li>
</ul>
</li>
<li><a class="reference internal" href="#operators-and-delimiters">2.7. Operators and delimiters</a></li>
</ul>
</li>
</ul>

  </div>
  <div>
    <h4>Previous topic</h4>
    <p class="topless"><a href="introduction.html"
                          title="previous chapter"><span class="section-number">1. </span>Introduction</a></p>
  </div>
  <div>
    <h4>Next topic</h4>
    <p class="topless"><a href="datamodel.html"
                          title="next chapter"><span class="section-number">3. </span>Data model</a></p>
  </div>
  <script>
    document.addEventListener('DOMContentLoaded', () => {
        const title = document.querySelector('meta[property="og:title"]').content;
        const elements = document.querySelectorAll('.improvepage');
        const pageurl = window.location.href.split('?')[0];
        elements.forEach(element => {
            const url = new URL(element.href.split('?')[0].replace("-nojs", ""));
            url.searchParams.set('pagetitle', title);
            url.searchParams.set('pageurl', pageurl);
            url.searchParams.set('pagesource', "reference/lexical_analysis.rst");
            element.href = url.toString();
        });
    });
  </script>
  <div role="note" aria-label="source link">
    <h3>This page</h3>
    <ul class="this-page-menu">
      <li><a href="../bugs.html">Report a bug</a></li>
      <li><a class="improvepage" href="../improve-page-nojs.html">Improve this page</a></li>
      <li>
        <a href="https://github.com/python/cpython/blob/main/Doc/reference/lexical_analysis.rst?plain=1"
            rel="nofollow">Show source
        </a>
      </li>
      
    </ul>
  </div>
        </nav>
    </div>
</div>

  
    <div class="related" role="navigation" aria-label="Related">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             accesskey="I">index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="datamodel.html" title="3. Data model"
             accesskey="N">next</a> |</li>
        <li class="right" >
          <a href="introduction.html" title="1. Introduction"
             accesskey="P">previous</a> |</li>

          <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"></li>
          <li><a href="https://www.python.org/">Python</a> &#187;</li>
          <li class="switchers">
            <div class="language_switcher_placeholder"></div>
            <div class="version_switcher_placeholder"></div>
          </li>
          <li>
              
          </li>
    <li id="cpython-language-and-version">
      <a href="../index.html">3.14.4 Documentation</a> &#187;
    </li>

          <li class="nav-item nav-item-1"><a href="index.html" accesskey="U">The Python Language Reference</a> &#187;</li>
        <li class="nav-item nav-item-this"><a href=""><span class="section-number">2. </span>Lexical analysis</a></li>
                <li class="right">
                    

    <div class="inline-search" role="search">
        <form class="inline-search" action="../search.html" method="get">
          <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box">
          <input type="submit" value="Go">
        </form>
    </div>
                     |
                </li>
            <li class="right">
<label class="theme-selector-label">
    Theme
    <select class="theme-selector" oninput="activateTheme(this.value)">
        <option value="auto" selected>Auto</option>
        <option value="light">Light</option>
        <option value="dark">Dark</option>
    </select>
</label> |</li>
            
      </ul>
    </div>    

    <div class="document">
      <div class="documentwrapper">
        <div class="bodywrapper">
          <div class="body" role="main">
            
  <section id="lexical-analysis">
<span id="lexical"></span><h1><span class="section-number">2. </span>Lexical analysis<a class="headerlink" href="#lexical-analysis" title="Link to this heading">¶</a></h1>
<p id="index-0">A Python program is read by a <em>parser</em>.  Input to the parser is a stream of
<a class="reference internal" href="../glossary.html#term-token"><span class="xref std std-term">tokens</span></a>, generated by the <em>lexical analyzer</em> (also known as
the <em>tokenizer</em>).
This chapter describes how the lexical analyzer produces these tokens.</p>
<p>The lexical analyzer determines the program text’s <a class="reference internal" href="#encodings"><span class="std std-ref">encoding</span></a>
(UTF-8 by default), and decodes the text into
<a class="reference internal" href="#lexical-source-character"><span class="std std-ref">source characters</span></a>.
If the text cannot be decoded, a <a class="reference internal" href="../library/exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SyntaxError</span></code></a> is raised.</p>
<p>Next, the lexical analyzer uses the source characters to generate a stream of tokens.
The type of a generated token generally depends on the next source character to
be processed. Similarly, other special behavior of the analyzer depends on
the first source character that hasn’t yet been processed.
The following table gives a quick summary of these source characters,
with links to sections that contain more information.</p>
<table class="docutils align-default">
<thead>
<tr class="row-odd"><th class="head"><p>Character</p></th>
<th class="head"><p>Next token (or other relevant documentation)</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><ul class="simple">
<li><p>space</p></li>
<li><p>tab</p></li>
<li><p>formfeed</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#whitespace"><span class="std std-ref">Whitespace</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-odd"><td><ul class="simple">
<li><p>CR, LF</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#line-structure"><span class="std std-ref">New line</span></a></p></li>
<li><p><a class="reference internal" href="#indentation"><span class="std std-ref">Indentation</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-even"><td><ul class="simple">
<li><p>backslash (<code class="docutils literal notranslate"><span class="pre">\</span></code>)</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#explicit-joining"><span class="std std-ref">Explicit line joining</span></a></p></li>
<li><p>(Also significant in <a class="reference internal" href="#escape-sequences"><span class="std std-ref">string escape sequences</span></a>)</p></li>
</ul>
</td>
</tr>
<tr class="row-odd"><td><ul class="simple">
<li><p>hash (<code class="docutils literal notranslate"><span class="pre">#</span></code>)</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#comments"><span class="std std-ref">Comment</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-even"><td><ul class="simple">
<li><p>quote (<code class="docutils literal notranslate"><span class="pre">'</span></code>, <code class="docutils literal notranslate"><span class="pre">&quot;</span></code>)</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#strings"><span class="std std-ref">String literal</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-odd"><td><ul class="simple">
<li><p>ASCII letter (<code class="docutils literal notranslate"><span class="pre">a</span></code>-<code class="docutils literal notranslate"><span class="pre">z</span></code>, <code class="docutils literal notranslate"><span class="pre">A</span></code>-<code class="docutils literal notranslate"><span class="pre">Z</span></code>)</p></li>
<li><p>non-ASCII character</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#identifiers"><span class="std std-ref">Name</span></a></p></li>
<li><p>Prefixed <a class="reference internal" href="#strings"><span class="std std-ref">string or bytes literal</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-even"><td><ul class="simple">
<li><p>underscore (<code class="docutils literal notranslate"><span class="pre">_</span></code>)</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#identifiers"><span class="std std-ref">Name</span></a></p></li>
<li><p>(Can also be part of <a class="reference internal" href="#numbers"><span class="std std-ref">numeric literals</span></a>)</p></li>
</ul>
</td>
</tr>
<tr class="row-odd"><td><ul class="simple">
<li><p>number (<code class="docutils literal notranslate"><span class="pre">0</span></code>-<code class="docutils literal notranslate"><span class="pre">9</span></code>)</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#numbers"><span class="std std-ref">Numeric literal</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-even"><td><ul class="simple">
<li><p>dot (<code class="docutils literal notranslate"><span class="pre">.</span></code>)</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#numbers"><span class="std std-ref">Numeric literal</span></a></p></li>
<li><p><a class="reference internal" href="#operators"><span class="std std-ref">Operator</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-odd"><td><ul class="simple">
<li><p>question mark (<code class="docutils literal notranslate"><span class="pre">?</span></code>)</p></li>
<li><p>dollar (<code class="docutils literal notranslate"><span class="pre">$</span></code>)</p></li>
<li><p>backquote (<code class="docutils literal notranslate"><span class="pre">`</span></code>)</p>
</li>
<li><p>control character</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p>Error (outside string literals and comments)</p></li>
</ul>
</td>
</tr>
<tr class="row-even"><td><ul class="simple">
<li><p>other printing character</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#operators"><span class="std std-ref">Operator or delimiter</span></a></p></li>
</ul>
</td>
</tr>
<tr class="row-odd"><td><ul class="simple">
<li><p>end of file</p></li>
</ul>
</td>
<td><ul class="simple">
<li><p><a class="reference internal" href="#endmarker-token"><span class="std std-ref">End marker</span></a></p></li>
</ul>
</td>
</tr>
</tbody>
</table>
<section id="line-structure">
<span id="id1"></span><h2><span class="section-number">2.1. </span>Line structure<a class="headerlink" href="#line-structure" title="Link to this heading">¶</a></h2>
<p id="index-1">A Python program is divided into a number of <em>logical lines</em>.</p>
<section id="logical-lines">
<span id="id2"></span><h3><span class="section-number">2.1.1. </span>Logical lines<a class="headerlink" href="#logical-lines" title="Link to this heading">¶</a></h3>
<p id="index-2">The end of a logical line is represented by the token <a class="reference internal" href="../library/token.html#token.NEWLINE" title="token.NEWLINE"><code class="xref py py-data docutils literal notranslate"><span class="pre">NEWLINE</span></code></a>.
Statements cannot cross logical line boundaries except where <code class="xref py py-data docutils literal notranslate"><span class="pre">NEWLINE</span></code>
is allowed by the syntax (e.g., between statements in compound statements).
A logical line is constructed from one or more <em>physical lines</em> by following
the <a class="reference internal" href="#explicit-joining"><span class="std std-ref">explicit</span></a> or <a class="reference internal" href="#implicit-joining"><span class="std std-ref">implicit</span></a>
<em>line joining</em> rules.</p>
</section>
<section id="physical-lines">
<span id="id3"></span><h3><span class="section-number">2.1.2. </span>Physical lines<a class="headerlink" href="#physical-lines" title="Link to this heading">¶</a></h3>
<p>A physical line is a sequence of characters terminated by one the following
end-of-line sequences:</p>
<ul class="simple">
<li><p>the Unix form using ASCII LF (linefeed),</p></li>
<li><p>the Windows form using the ASCII sequence CR LF (return followed by linefeed),</p></li>
<li><p>the ‘<a class="reference external" href="https://en.wikipedia.org/wiki/Classic_Mac_OS">Classic Mac OS</a>’ form using the ASCII CR (return) character.</p>
</li>
</ul>
<p>Regardless of platform, each of these sequences is replaced by a single
ASCII LF (linefeed) character.
(This is done even inside <a class="reference internal" href="#strings"><span class="std std-ref">string literals</span></a>.)
Each line can use any of the sequences; they do not need to be consistent
within a file.</p>
<p>The end of input also serves as an implicit terminator for the final
physical line.</p>
<p>Formally:</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-newline">newline</strong>: &lt;ASCII LF&gt; | &lt;ASCII CR&gt; &lt;ASCII LF&gt; | &lt;ASCII CR&gt;
</pre>
</section>
<section id="comments">
<span id="id5"></span><h3><span class="section-number">2.1.3. </span>Comments<a class="headerlink" href="#comments" title="Link to this heading">¶</a></h3>
<p id="index-3">A comment starts with a hash character (<code class="docutils literal notranslate"><span class="pre">#</span></code>) that is not part of a string
literal, and ends at the end of the physical line.  A comment signifies the end
of the logical line unless the implicit line joining rules are invoked. Comments
are ignored by the syntax.</p>
</section>
<section id="encoding-declarations">
<span id="encodings"></span><h3><span class="section-number">2.1.4. </span>Encoding declarations<a class="headerlink" href="#encoding-declarations" title="Link to this heading">¶</a></h3>
<p id="index-4">If a comment in the first or second line of the Python script matches the
regular expression <code class="docutils literal notranslate"><span class="pre">coding[=:]\s*([-\w.]+)</span></code>, this comment is processed as an
encoding declaration; the first group of this expression names the encoding of
the source code file. The encoding declaration must appear on a line of its
own. If it is the second line, the first line must also be a comment-only line.
The recommended forms of an encoding expression are</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="c1"># -*- coding: &lt;encoding-name&gt; -*-</span>
</pre></div>
</div>
<p>which is recognized also by GNU Emacs, and</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="c1"># vim:fileencoding=&lt;encoding-name&gt;</span>
</pre></div>
</div>
<p>which is recognized by Bram Moolenaar’s VIM.</p>
<p>If no encoding declaration is found, the default encoding is UTF-8.  If the
implicit or explicit encoding of a file is UTF-8, an initial UTF-8 byte-order
mark (<code class="docutils literal notranslate"><span class="pre">b'\xef\xbb\xbf'</span></code>) is ignored rather than being a syntax error.</p>
<p>If an encoding is declared, the encoding name must be recognized by Python
(see <a class="reference internal" href="../library/codecs.html#standard-encodings"><span class="std std-ref">Standard Encodings</span></a>). The
encoding is used for all lexical analysis, including string literals, comments
and identifiers.</p>
<p id="lexical-source-character">All lexical analysis, including string literals, comments
and identifiers, works on Unicode text decoded using the source encoding.
Any Unicode code point, except the NUL control character, can appear in
Python source.</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-source_character">source_character</strong>:  &lt;any Unicode code point, except NUL&gt;
</pre>
</section>
<section id="explicit-line-joining">
<span id="explicit-joining"></span><h3><span class="section-number">2.1.5. </span>Explicit line joining<a class="headerlink" href="#explicit-line-joining" title="Link to this heading">¶</a></h3>
<p id="index-5">Two or more physical lines may be joined into logical lines using backslash
characters (<code class="docutils literal notranslate"><span class="pre">\</span></code>), as follows: when a physical line ends in a backslash that is
not part of a string literal or comment, it is joined with the following forming
a single logical line, deleting the backslash and the following end-of-line
character.  For example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">if</span> <span class="mi">1900</span> <span class="o">&lt;</span> <span class="n">year</span> <span class="o">&lt;</span> <span class="mi">2100</span> <span class="ow">and</span> <span class="mi">1</span> <span class="o">&lt;=</span> <span class="n">month</span> <span class="o">&lt;=</span> <span class="mi">12</span> \
   <span class="ow">and</span> <span class="mi">1</span> <span class="o">&lt;=</span> <span class="n">day</span> <span class="o">&lt;=</span> <span class="mi">31</span> <span class="ow">and</span> <span class="mi">0</span> <span class="o">&lt;=</span> <span class="n">hour</span> <span class="o">&lt;</span> <span class="mi">24</span> \
   <span class="ow">and</span> <span class="mi">0</span> <span class="o">&lt;=</span> <span class="n">minute</span> <span class="o">&lt;</span> <span class="mi">60</span> <span class="ow">and</span> <span class="mi">0</span> <span class="o">&lt;=</span> <span class="n">second</span> <span class="o">&lt;</span> <span class="mi">60</span><span class="p">:</span>   <span class="c1"># Looks like a valid date</span>
        <span class="k">return</span> <span class="mi">1</span>
</pre></div>
</div>
<p>A line ending in a backslash cannot carry a comment.  A backslash does not
continue a comment.  A backslash does not continue a token except for string
literals (i.e., tokens other than string literals cannot be split across
physical lines using a backslash).  A backslash is illegal elsewhere on a line
outside a string literal.</p>
</section>
<section id="implicit-line-joining">
<span id="implicit-joining"></span><h3><span class="section-number">2.1.6. </span>Implicit line joining<a class="headerlink" href="#implicit-line-joining" title="Link to this heading">¶</a></h3>
<p>Expressions in parentheses, square brackets or curly braces can be split over
more than one physical line without using backslashes. For example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">month_names</span> <span class="o">=</span> <span class="p">[</span><span class="s1">&#39;Januari&#39;</span><span class="p">,</span> <span class="s1">&#39;Februari&#39;</span><span class="p">,</span> <span class="s1">&#39;Maart&#39;</span><span class="p">,</span>      <span class="c1"># These are the</span>
               <span class="s1">&#39;April&#39;</span><span class="p">,</span>   <span class="s1">&#39;Mei&#39;</span><span class="p">,</span>      <span class="s1">&#39;Juni&#39;</span><span class="p">,</span>       <span class="c1"># Dutch names</span>
               <span class="s1">&#39;Juli&#39;</span><span class="p">,</span>    <span class="s1">&#39;Augustus&#39;</span><span class="p">,</span> <span class="s1">&#39;September&#39;</span><span class="p">,</span>  <span class="c1"># for the months</span>
               <span class="s1">&#39;Oktober&#39;</span><span class="p">,</span> <span class="s1">&#39;November&#39;</span><span class="p">,</span> <span class="s1">&#39;December&#39;</span><span class="p">]</span>   <span class="c1"># of the year</span>
</pre></div>
</div>
<p>Implicitly continued lines can carry comments.  The indentation of the
continuation lines is not important.  Blank continuation lines are allowed.
There is no NEWLINE token between implicit continuation lines.  Implicitly
continued lines can also occur within triple-quoted strings (see below); in that
case they cannot carry comments.</p>
</section>
<section id="blank-lines">
<span id="id6"></span><h3><span class="section-number">2.1.7. </span>Blank lines<a class="headerlink" href="#blank-lines" title="Link to this heading">¶</a></h3>
<p id="index-6">A logical line that contains only spaces, tabs, formfeeds and possibly a
comment, is ignored (i.e., no <a class="reference internal" href="../library/token.html#token.NEWLINE" title="token.NEWLINE"><code class="xref py py-data docutils literal notranslate"><span class="pre">NEWLINE</span></code></a> token is generated).
During interactive input of statements, handling of a blank line may differ
depending on the implementation of the read-eval-print loop.
In the standard interactive interpreter, an entirely blank logical line (that
is, one containing not even whitespace or a comment) terminates a multi-line
statement.</p>
</section>
<section id="indentation">
<span id="id7"></span><h3><span class="section-number">2.1.8. </span>Indentation<a class="headerlink" href="#indentation" title="Link to this heading">¶</a></h3>
<p id="index-7">Leading whitespace (spaces and tabs) at the beginning of a logical line is used
to compute the indentation level of the line, which in turn is used to determine
the grouping of statements.</p>
<p>Tabs are replaced (from left to right) by one to eight spaces such that the
total number of characters up to and including the replacement is a multiple of
eight (this is intended to be the same rule as used by Unix).  The total number
of spaces preceding the first non-blank character then determines the line’s
indentation.  Indentation cannot be split over multiple physical lines using
backslashes; the whitespace up to the first backslash determines the
indentation.</p>
<p>Indentation is rejected as inconsistent if a source file mixes tabs and spaces
in a way that makes the meaning dependent on the worth of a tab in spaces; a
<a class="reference internal" href="../library/exceptions.html#TabError" title="TabError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TabError</span></code></a> is raised in that case.</p>
<p><strong>Cross-platform compatibility note:</strong> because of the nature of text editors on
non-UNIX platforms, it is unwise to use a mixture of spaces and tabs for the
indentation in a single source file.  It should also be noted that different
platforms may explicitly limit the maximum indentation level.</p>
<p>A formfeed character may be present at the start of the line; it will be ignored
for the indentation calculations above.  Formfeed characters occurring elsewhere
in the leading whitespace have an undefined effect (for instance, they may reset
the space count to zero).</p>
<p id="index-8">The indentation levels of consecutive lines are used to generate
<a class="reference internal" href="../library/token.html#token.INDENT" title="token.INDENT"><code class="xref py py-data docutils literal notranslate"><span class="pre">INDENT</span></code></a> and <a class="reference internal" href="../library/token.html#token.DEDENT" title="token.DEDENT"><code class="xref py py-data docutils literal notranslate"><span class="pre">DEDENT</span></code></a> tokens, using a stack,
as follows.</p>
<p>Before the first line of the file is read, a single zero is pushed on the stack;
this will never be popped off again.  The numbers pushed on the stack will
always be strictly increasing from bottom to top.  At the beginning of each
logical line, the line’s indentation level is compared to the top of the stack.
If it is equal, nothing happens. If it is larger, it is pushed on the stack, and
one <code class="xref py py-data docutils literal notranslate"><span class="pre">INDENT</span></code> token is generated.  If it is smaller, it <em>must</em> be one of the
numbers occurring on the stack; all numbers on the stack that are larger are
popped off, and for each number popped off a <code class="xref py py-data docutils literal notranslate"><span class="pre">DEDENT</span></code> token is generated.
At the end of the file, a <code class="xref py py-data docutils literal notranslate"><span class="pre">DEDENT</span></code> token is generated for each number
remaining on the stack that is larger than zero.</p>
<p>Here is an example of a correctly (though confusingly) indented piece of Python
code:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">perm</span><span class="p">(</span><span class="n">l</span><span class="p">):</span>
        <span class="c1"># Compute the list of all permutations of l</span>
    <span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">l</span><span class="p">)</span> <span class="o">&lt;=</span> <span class="mi">1</span><span class="p">:</span>
                  <span class="k">return</span> <span class="p">[</span><span class="n">l</span><span class="p">]</span>
    <span class="n">r</span> <span class="o">=</span> <span class="p">[]</span>
    <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">l</span><span class="p">)):</span>
             <span class="n">s</span> <span class="o">=</span> <span class="n">l</span><span class="p">[:</span><span class="n">i</span><span class="p">]</span> <span class="o">+</span> <span class="n">l</span><span class="p">[</span><span class="n">i</span><span class="o">+</span><span class="mi">1</span><span class="p">:]</span>
             <span class="n">p</span> <span class="o">=</span> <span class="n">perm</span><span class="p">(</span><span class="n">s</span><span class="p">)</span>
             <span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="n">p</span><span class="p">:</span>
              <span class="n">r</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">l</span><span class="p">[</span><span class="n">i</span><span class="p">:</span><span class="n">i</span><span class="o">+</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">x</span><span class="p">)</span>
    <span class="k">return</span> <span class="n">r</span>
</pre></div>
</div>
<p>The following example shows various indentation errors:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span> <span class="k">def</span><span class="w"> </span><span class="nf">perm</span><span class="p">(</span><span class="n">l</span><span class="p">):</span>                       <span class="c1"># error: first line indented</span>
<span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">l</span><span class="p">)):</span>             <span class="c1"># error: not indented</span>
    <span class="n">s</span> <span class="o">=</span> <span class="n">l</span><span class="p">[:</span><span class="n">i</span><span class="p">]</span> <span class="o">+</span> <span class="n">l</span><span class="p">[</span><span class="n">i</span><span class="o">+</span><span class="mi">1</span><span class="p">:]</span>
        <span class="n">p</span> <span class="o">=</span> <span class="n">perm</span><span class="p">(</span><span class="n">l</span><span class="p">[:</span><span class="n">i</span><span class="p">]</span> <span class="o">+</span> <span class="n">l</span><span class="p">[</span><span class="n">i</span><span class="o">+</span><span class="mi">1</span><span class="p">:])</span>   <span class="c1"># error: unexpected indent</span>
        <span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="n">p</span><span class="p">:</span>
                <span class="n">r</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">l</span><span class="p">[</span><span class="n">i</span><span class="p">:</span><span class="n">i</span><span class="o">+</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">x</span><span class="p">)</span>
            <span class="k">return</span> <span class="n">r</span>                <span class="c1"># error: inconsistent dedent</span>
</pre></div>
</div>
<p>(Actually, the first three errors are detected by the parser; only the last
error is found by the lexical analyzer — the indentation of <code class="docutils literal notranslate"><span class="pre">return</span> <span class="pre">r</span></code> does
not match a level popped off the stack.)</p>
</section>
<section id="whitespace-between-tokens">
<span id="whitespace"></span><h3><span class="section-number">2.1.9. </span>Whitespace between tokens<a class="headerlink" href="#whitespace-between-tokens" title="Link to this heading">¶</a></h3>
<p>Except at the beginning of a logical line or in string literals, the whitespace
characters space, tab and formfeed can be used interchangeably to separate
tokens:</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-whitespace">whitespace</strong>:  <span class="sx">' '</span> | tab | formfeed
</pre>
<p>Whitespace is needed between two tokens only if their concatenation
could otherwise be interpreted as a different token. For example, <code class="docutils literal notranslate"><span class="pre">ab</span></code> is one
token, but <code class="docutils literal notranslate"><span class="pre">a</span> <span class="pre">b</span></code> is two tokens. However, <code class="docutils literal notranslate"><span class="pre">+a</span></code> and <code class="docutils literal notranslate"><span class="pre">+</span> <span class="pre">a</span></code> both produce
two tokens, <code class="docutils literal notranslate"><span class="pre">+</span></code> and <code class="docutils literal notranslate"><span class="pre">a</span></code>, as <code class="docutils literal notranslate"><span class="pre">+a</span></code> is not a valid token.</p>
</section>
<section id="end-marker">
<span id="endmarker-token"></span><h3><span class="section-number">2.1.10. </span>End marker<a class="headerlink" href="#end-marker" title="Link to this heading">¶</a></h3>
<p>At the end of non-interactive input, the lexical analyzer generates an
<a class="reference internal" href="../library/token.html#token.ENDMARKER" title="token.ENDMARKER"><code class="xref py py-data docutils literal notranslate"><span class="pre">ENDMARKER</span></code></a> token.</p>
</section>
</section>
<section id="other-tokens">
<span id="id8"></span><h2><span class="section-number">2.2. </span>Other tokens<a class="headerlink" href="#other-tokens" title="Link to this heading">¶</a></h2>
<p>Besides <a class="reference internal" href="../library/token.html#token.NEWLINE" title="token.NEWLINE"><code class="xref py py-data docutils literal notranslate"><span class="pre">NEWLINE</span></code></a>, <a class="reference internal" href="../library/token.html#token.INDENT" title="token.INDENT"><code class="xref py py-data docutils literal notranslate"><span class="pre">INDENT</span></code></a> and <a class="reference internal" href="../library/token.html#token.DEDENT" title="token.DEDENT"><code class="xref py py-data docutils literal notranslate"><span class="pre">DEDENT</span></code></a>,
the following categories of tokens exist:
<em>identifiers</em> and <em>keywords</em> (<a class="reference internal" href="../library/token.html#token.NAME" title="token.NAME"><code class="xref py py-data docutils literal notranslate"><span class="pre">NAME</span></code></a>), <em>literals</em> (such as
<a class="reference internal" href="../library/token.html#token.NUMBER" title="token.NUMBER"><code class="xref py py-data docutils literal notranslate"><span class="pre">NUMBER</span></code></a> and <a class="reference internal" href="../library/token.html#token.STRING" title="token.STRING"><code class="xref py py-data docutils literal notranslate"><span class="pre">STRING</span></code></a>), and other symbols
(<em>operators</em> and <em>delimiters</em>, <a class="reference internal" href="../library/token.html#token.OP" title="token.OP"><code class="xref py py-data docutils literal notranslate"><span class="pre">OP</span></code></a>).
Whitespace characters (other than logical line terminators, discussed earlier)
are not tokens, but serve to delimit tokens.
Where ambiguity exists, a token comprises the longest possible string that
forms a legal token, when read from left to right.</p>
</section>
<section id="names-identifiers-and-keywords">
<span id="identifiers"></span><h2><span class="section-number">2.3. </span>Names (identifiers and keywords)<a class="headerlink" href="#names-identifiers-and-keywords" title="Link to this heading">¶</a></h2>
<p id="index-9"><a class="reference internal" href="../library/token.html#token.NAME" title="token.NAME"><code class="xref py py-data docutils literal notranslate"><span class="pre">NAME</span></code></a> tokens represent <em>identifiers</em>, <em>keywords</em>, and
<em>soft keywords</em>.</p>
<p>Names are composed of the following characters:</p>
<ul class="simple">
<li><p>uppercase and lowercase letters (<code class="docutils literal notranslate"><span class="pre">A-Z</span></code> and <code class="docutils literal notranslate"><span class="pre">a-z</span></code>),</p></li>
<li><p>the underscore (<code class="docutils literal notranslate"><span class="pre">_</span></code>),</p></li>
<li><p>digits (<code class="docutils literal notranslate"><span class="pre">0</span></code> through <code class="docutils literal notranslate"><span class="pre">9</span></code>), which cannot appear as the first character, and</p></li>
<li><p>non-ASCII characters. Valid names may only contain “letter-like” and
“digit-like” characters; see <a class="reference internal" href="#lexical-names-nonascii"><span class="std std-ref">Non-ASCII characters in names</span></a> for details.</p></li>
</ul>
<p>Names must contain at least one character, but have no upper length limit.
Case is significant.</p>
<p>Formally, names are described by the following lexical definitions:</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-NAME">NAME</strong>:          <a class="reference internal" href="#grammar-token-python-grammar-name_start"><code class="xref docutils literal notranslate"><span class="pre">name_start</span></code></a> <a class="reference internal" href="#grammar-token-python-grammar-name_continue"><code class="xref docutils literal notranslate"><span class="pre">name_continue</span></code></a>*
<strong id="grammar-token-python-grammar-name_start">name_start</strong>:    <span class="sx">&quot;a&quot;</span>...<span class="sx">&quot;z&quot;</span> | <span class="sx">&quot;A&quot;</span>...<span class="sx">&quot;Z&quot;</span> | <span class="sx">&quot;_&quot;</span> | &lt;non-ASCII character&gt;
<strong id="grammar-token-python-grammar-name_continue">name_continue</strong>: name_start | <span class="sx">&quot;0&quot;</span>...<span class="sx">&quot;9&quot;</span>
<strong id="grammar-token-python-grammar-identifier">identifier</strong>:    &lt;<a class="reference internal" href="#grammar-token-python-grammar-NAME"><code class="xref docutils literal notranslate"><span class="pre">NAME</span></code></a>, except keywords&gt;
</pre>
<p>Note that not all names matched by this grammar are valid; see
<a class="reference internal" href="#lexical-names-nonascii"><span class="std std-ref">Non-ASCII characters in names</span></a> for details.</p>
<section id="keywords">
<span id="id9"></span><h3><span class="section-number">2.3.1. </span>Keywords<a class="headerlink" href="#keywords" title="Link to this heading">¶</a></h3>
<p id="index-10">The following names are used as reserved words, or <em>keywords</em> of the
language, and cannot be used as ordinary identifiers.  They must be spelled
exactly as written here:</p>
<div class="highlight-text notranslate"><div class="highlight"><pre><span></span>False      await      else       import     pass
None       break      except     in         raise
True       class      finally    is         return
and        continue   for        lambda     try
as         def        from       nonlocal   while
assert     del        global     not        with
async      elif       if         or         yield
</pre></div>
</div>
</section>
<section id="soft-keywords">
<span id="id10"></span><h3><span class="section-number">2.3.2. </span>Soft Keywords<a class="headerlink" href="#soft-keywords" title="Link to this heading">¶</a></h3>
<div class="versionadded" id="index-11">
<p><span class="versionmodified added">Added in version 3.10.</span></p>
</div>
<p>Some names are only reserved under specific contexts. These are known as
<em>soft keywords</em>:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">match</span></code>, <code class="docutils literal notranslate"><span class="pre">case</span></code>, and <code class="docutils literal notranslate"><span class="pre">_</span></code>, when used in the <a class="reference internal" href="compound_stmts.html#match"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">match</span></code></a> statement.</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">type</span></code>, when used in the <a class="reference internal" href="simple_stmts.html#type"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">type</span></code></a> statement.</p></li>
</ul>
<p>These syntactically act as keywords in their specific contexts,
but this distinction is done at the parser level, not when tokenizing.</p>
<p>As soft keywords, their use in the grammar is possible while still
preserving compatibility with existing code that uses these names as
identifier names.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.12: </span><code class="docutils literal notranslate"><span class="pre">type</span></code> is now a soft keyword.</p>
</div>
</section>
<section id="reserved-classes-of-identifiers">
<span id="id-classes"></span><span id="index-12"></span><h3><span class="section-number">2.3.3. </span>Reserved classes of identifiers<a class="headerlink" href="#reserved-classes-of-identifiers" title="Link to this heading">¶</a></h3>
<p>Certain classes of identifiers (besides keywords) have special meanings.  These
classes are identified by the patterns of leading and trailing underscore
characters:</p>
<dl>
<dt><code class="docutils literal notranslate"><span class="pre">_*</span></code></dt><dd><p>Not imported by <code class="docutils literal notranslate"><span class="pre">from</span> <span class="pre">module</span> <span class="pre">import</span> <span class="pre">*</span></code>.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">_</span></code></dt><dd><p>In a <code class="docutils literal notranslate"><span class="pre">case</span></code> pattern within a <a class="reference internal" href="compound_stmts.html#match"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">match</span></code></a> statement, <code class="docutils literal notranslate"><span class="pre">_</span></code> is a
<a class="reference internal" href="#soft-keywords"><span class="std std-ref">soft keyword</span></a> that denotes a
<a class="reference internal" href="compound_stmts.html#wildcard-patterns"><span class="std std-ref">wildcard</span></a>.</p>
<p>Separately, the interactive interpreter makes the result of the last evaluation
available in the variable <code class="docutils literal notranslate"><span class="pre">_</span></code>.
(It is stored in the <a class="reference internal" href="../library/builtins.html#module-builtins" title="builtins: The module that provides the built-in namespace."><code class="xref py py-mod docutils literal notranslate"><span class="pre">builtins</span></code></a> module, alongside built-in
functions like <code class="docutils literal notranslate"><span class="pre">print</span></code>.)</p>
<p>Elsewhere, <code class="docutils literal notranslate"><span class="pre">_</span></code> is a regular identifier. It is often used to name
“special” items, but it is not special to Python itself.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>The name <code class="docutils literal notranslate"><span class="pre">_</span></code> is often used in conjunction with internationalization;
refer to the documentation for the <a class="reference internal" href="../library/gettext.html#module-gettext" title="gettext: Multilingual internationalization services."><code class="xref py py-mod docutils literal notranslate"><span class="pre">gettext</span></code></a> module for more
information on this convention.</p>
<p>It is also commonly used for unused variables.</p>
</div>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">__*__</span></code></dt><dd><p>System-defined names, informally known as “dunder” names. These names are
defined by the interpreter and its implementation (including the standard library).
Current system names are discussed in the <a class="reference internal" href="datamodel.html#specialnames"><span class="std std-ref">Special method names</span></a> section and elsewhere.
More will likely be defined in future versions of Python.  <em>Any</em> use of <code class="docutils literal notranslate"><span class="pre">__*__</span></code> names,
in any context, that does not follow explicitly documented use, is subject to
breakage without warning.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">__*</span></code></dt><dd><p>Class-private names.  Names in this category, when used within the context of a
class definition, are re-written to use a mangled form to help avoid name
clashes between “private” attributes of base and derived classes. See section
<a class="reference internal" href="expressions.html#atom-identifiers"><span class="std std-ref">Identifiers (Names)</span></a>.</p>
</dd>
</dl>
</section>
<section id="non-ascii-characters-in-names">
<span id="lexical-names-nonascii"></span><h3><span class="section-number">2.3.4. </span>Non-ASCII characters in names<a class="headerlink" href="#non-ascii-characters-in-names" title="Link to this heading">¶</a></h3>
<p>Names that contain non-ASCII characters need additional normalization
and validation beyond the rules and grammar explained
<a class="reference internal" href="#identifiers"><span class="std std-ref">above</span></a>.
For example, <code class="docutils literal notranslate"><span class="pre">ř_1</span></code>, <code class="docutils literal notranslate"><span class="pre">蛇</span></code>, or <code class="docutils literal notranslate"><span class="pre">साँप</span></code>  are valid names, but <code class="docutils literal notranslate"><span class="pre">r〰2</span></code>,
<code class="docutils literal notranslate"><span class="pre">€</span></code>, or <code class="docutils literal notranslate"><span class="pre">🐍</span></code> are not.</p>
<p>This section explains the exact rules.</p>
<p>All names are converted into the <a class="reference external" href="https://www.unicode.org/reports/tr15/#Norm_Forms">normalization form</a> NFKC while parsing.
This means that, for example, some typographic variants of characters are
converted to their “basic” form. For example, <code class="docutils literal notranslate"><span class="pre">ﬁⁿₐˡᵢᶻₐᵗᵢᵒₙ</span></code> normalizes to
<code class="docutils literal notranslate"><span class="pre">finalization</span></code>, so Python treats them as the same name:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">ﬁⁿₐˡᵢᶻₐᵗᵢᵒₙ</span> <span class="o">=</span> <span class="mi">3</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">finalization</span>
<span class="go">3</span>
</pre></div>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>Normalization is done at the lexical level only.
Run-time functions that take names as <em>strings</em> generally do not normalize
their arguments.
For example, the variable defined above is accessible at run time in the
<a class="reference internal" href="../library/functions.html#globals" title="globals"><code class="xref py py-func docutils literal notranslate"><span class="pre">globals()</span></code></a> dictionary as <code class="docutils literal notranslate"><span class="pre">globals()[&quot;finalization&quot;]</span></code> but not
<code class="docutils literal notranslate"><span class="pre">globals()[&quot;ﬁⁿₐˡᵢᶻₐᵗᵢᵒₙ&quot;]</span></code>.</p>
</div>
<p>Similarly to how ASCII-only names must contain only letters, digits and
the underscore, and cannot start with a digit, a valid name must
start with a character in the “letter-like” set <code class="docutils literal notranslate"><span class="pre">xid_start</span></code>,
and the remaining characters must be in the “letter- and digit-like” set
<code class="docutils literal notranslate"><span class="pre">xid_continue</span></code>.</p>
<p>These sets are based on the <em>XID_Start</em> and <em>XID_Continue</em> sets as defined by the
Unicode standard annex <a class="reference external" href="https://www.unicode.org/reports/tr31/">UAX-31</a>.
Python’s <code class="docutils literal notranslate"><span class="pre">xid_start</span></code> additionally includes the underscore (<code class="docutils literal notranslate"><span class="pre">_</span></code>).
Note that Python does not necessarily conform to <a class="reference external" href="https://www.unicode.org/reports/tr31/">UAX-31</a>.</p>
<p>A non-normative listing of characters in the <em>XID_Start</em> and <em>XID_Continue</em>
sets as defined by Unicode is available in the <a class="reference external" href="https://www.unicode.org/Public/16.0.0/ucd/DerivedCoreProperties.txt">DerivedCoreProperties.txt</a>
file in the Unicode Character Database.
For reference, the construction rules for the <code class="docutils literal notranslate"><span class="pre">xid_*</span></code> sets are given below.</p>
<p>The set <code class="docutils literal notranslate"><span class="pre">id_start</span></code> is defined as the union of:</p>
<ul class="simple">
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Lu&gt;</span></code> - uppercase letters (includes <code class="docutils literal notranslate"><span class="pre">A</span></code> to <code class="docutils literal notranslate"><span class="pre">Z</span></code>)</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Ll&gt;</span></code> - lowercase letters (includes <code class="docutils literal notranslate"><span class="pre">a</span></code> to <code class="docutils literal notranslate"><span class="pre">z</span></code>)</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Lt&gt;</span></code> - titlecase letters</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Lm&gt;</span></code> - modifier letters</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Lo&gt;</span></code> - other letters</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Nl&gt;</span></code> - letter numbers</p></li>
<li><p>{<code class="docutils literal notranslate"><span class="pre">&quot;_&quot;</span></code>} - the underscore</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">&lt;Other_ID_Start&gt;</span></code> - an explicit set of characters in <a class="reference external" href="https://www.unicode.org/Public/16.0.0/ucd/PropList.txt">PropList.txt</a>
to support backwards compatibility</p></li>
</ul>
<p>The set <code class="docutils literal notranslate"><span class="pre">xid_start</span></code> then closes this set under NFKC normalization, by
removing all characters whose normalization is not of the form
<code class="docutils literal notranslate"><span class="pre">id_start</span> <span class="pre">id_continue*</span></code>.</p>
<p>The set <code class="docutils literal notranslate"><span class="pre">id_continue</span></code> is defined as the union of:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">id_start</span></code> (see above)</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Nd&gt;</span></code> - decimal numbers (includes <code class="docutils literal notranslate"><span class="pre">0</span></code> to <code class="docutils literal notranslate"><span class="pre">9</span></code>)</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Pc&gt;</span></code> - connector punctuations</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Mn&gt;</span></code> - nonspacing marks</p></li>
<li><p>Unicode category <code class="docutils literal notranslate"><span class="pre">&lt;Mc&gt;</span></code> - spacing combining marks</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">&lt;Other_ID_Continue&gt;</span></code> - another explicit set of characters in
<a class="reference external" href="https://www.unicode.org/Public/16.0.0/ucd/PropList.txt">PropList.txt</a> to support backwards compatibility</p></li>
</ul>
<p>Again, <code class="docutils literal notranslate"><span class="pre">xid_continue</span></code> closes this set under NFKC normalization.</p>
<p>Unicode categories use the version of the Unicode Character Database as
included in the <a class="reference internal" href="../library/unicodedata.html#module-unicodedata" title="unicodedata: Access the Unicode Database."><code class="xref py py-mod docutils literal notranslate"><span class="pre">unicodedata</span></code></a> module.</p>
<div class="admonition seealso">
<p class="admonition-title">See also</p>
<ul class="simple">
<li><p><span class="target" id="index-13"></span><a class="pep reference external" href="https://peps.python.org/pep-3131/"><strong>PEP 3131</strong></a> – Supporting Non-ASCII Identifiers</p></li>
<li><p><span class="target" id="index-14"></span><a class="pep reference external" href="https://peps.python.org/pep-0672/"><strong>PEP 672</strong></a> – Unicode-related Security Considerations for Python</p></li>
</ul>
</div>
</section>
</section>
<section id="literals">
<span id="id11"></span><h2><span class="section-number">2.4. </span>Literals<a class="headerlink" href="#literals" title="Link to this heading">¶</a></h2>
<p id="index-15">Literals are notations for constant values of some built-in types.</p>
<p>In terms of lexical analysis, Python has <a class="reference internal" href="#strings"><span class="std std-ref">string, bytes</span></a>
and <a class="reference internal" href="#numbers"><span class="std std-ref">numeric</span></a> literals.</p>
<p>Other “literals” are lexically denoted using <a class="reference internal" href="#keywords"><span class="std std-ref">keywords</span></a>
(<code class="docutils literal notranslate"><span class="pre">None</span></code>, <code class="docutils literal notranslate"><span class="pre">True</span></code>, <code class="docutils literal notranslate"><span class="pre">False</span></code>) and the special
<a class="reference internal" href="#lexical-ellipsis"><span class="std std-ref">ellipsis token</span></a> (<code class="docutils literal notranslate"><span class="pre">...</span></code>).</p>
</section>
<section id="string-and-bytes-literals">
<span id="strings"></span><span id="index-16"></span><h2><span class="section-number">2.5. </span>String and Bytes literals<a class="headerlink" href="#string-and-bytes-literals" title="Link to this heading">¶</a></h2>
<p>String literals are text enclosed in single quotes (<code class="docutils literal notranslate"><span class="pre">'</span></code>) or double
quotes (<code class="docutils literal notranslate"><span class="pre">&quot;</span></code>). For example:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="s2">&quot;spam&quot;</span>
<span class="s1">&#39;eggs&#39;</span>
</pre></div>
</div>
<p>The quote used to start the literal also terminates it, so a string literal
can only contain the other quote (except with escape sequences, see below).
For example:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="s1">&#39;Say &quot;Hello&quot;, please.&#39;</span>
<span class="s2">&quot;Don&#39;t do that!&quot;</span>
</pre></div>
</div>
<p>Except for this limitation, the choice of quote character (<code class="docutils literal notranslate"><span class="pre">'</span></code> or <code class="docutils literal notranslate"><span class="pre">&quot;</span></code>)
does not affect how the literal is parsed.</p>
<p>Inside a string literal, the backslash (<code class="docutils literal notranslate"><span class="pre">\</span></code>) character introduces an
<em class="dfn">escape sequence</em>, which has special meaning depending on the character
after the backslash.
For example, <code class="docutils literal notranslate"><span class="pre">\&quot;</span></code> denotes the double quote character, and does <em>not</em> end
the string:</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="s2">&quot;Say </span><span class="se">\&quot;</span><span class="s2">Hello</span><span class="se">\&quot;</span><span class="s2"> to everyone!&quot;</span><span class="p">)</span>
<span class="go">Say &quot;Hello&quot; to everyone!</span>
</pre></div>
</div>
<p>See <a class="reference internal" href="#escape-sequences"><span class="std std-ref">escape sequences</span></a> below for a full list of such
sequences, and more details.</p>
<section id="triple-quoted-strings">
<span id="index-17"></span><h3><span class="section-number">2.5.1. </span>Triple-quoted strings<a class="headerlink" href="#triple-quoted-strings" title="Link to this heading">¶</a></h3>
<p>Strings can also be enclosed in matching groups of three single or double
quotes.
These are generally referred to as <em class="dfn">triple-quoted strings</em>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="sd">&quot;&quot;&quot;This is a triple-quoted string.&quot;&quot;&quot;</span>
</pre></div>
</div>
<p>In triple-quoted literals, unescaped quotes are allowed (and are
retained), except that three unescaped quotes in a row terminate the literal,
if they are of the same kind (<code class="docutils literal notranslate"><span class="pre">'</span></code> or <code class="docutils literal notranslate"><span class="pre">&quot;</span></code>) used at the start:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="sd">&quot;&quot;&quot;This string has &quot;quotes&quot; inside.&quot;&quot;&quot;</span>
</pre></div>
</div>
<p>Unescaped newlines are also allowed and retained:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="sd">&#39;&#39;&#39;This triple-quoted string</span>
<span class="sd">continues on the next line.&#39;&#39;&#39;</span>
</pre></div>
</div>
</section>
<section id="string-prefixes">
<span id="index-18"></span><h3><span class="section-number">2.5.2. </span>String prefixes<a class="headerlink" href="#string-prefixes" title="Link to this heading">¶</a></h3>
<p>String literals can have an optional <em class="dfn">prefix</em> that influences how the
content of the literal is parsed, for example:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="sa">b</span><span class="s2">&quot;data&quot;</span>
<span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">result</span><span class="si">=}</span><span class="s1">&#39;</span>
</pre></div>
</div>
<p>The allowed prefixes are:</p>
<ul class="simple">
<li><p><code class="docutils literal notranslate"><span class="pre">b</span></code>: <a class="reference internal" href="#bytes-literal"><span class="std std-ref">Bytes literal</span></a></p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">r</span></code>: <a class="reference internal" href="#raw-strings"><span class="std std-ref">Raw string</span></a></p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">f</span></code>: <a class="reference internal" href="#f-strings"><span class="std std-ref">Formatted string literal</span></a> (“f-string”)</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">t</span></code>: <a class="reference internal" href="#t-strings"><span class="std std-ref">Template string literal</span></a> (“t-string”)</p></li>
<li><p><code class="docutils literal notranslate"><span class="pre">u</span></code>: No effect (allowed for backwards compatibility)</p></li>
</ul>
<p>See the linked sections for details on each type.</p>
<p>Prefixes are case-insensitive (for example, ‘<code class="docutils literal notranslate"><span class="pre">B</span></code>’ works the same as ‘<code class="docutils literal notranslate"><span class="pre">b</span></code>’).
The ‘<code class="docutils literal notranslate"><span class="pre">r</span></code>’ prefix can be combined with ‘<code class="docutils literal notranslate"><span class="pre">f</span></code>’, ‘<code class="docutils literal notranslate"><span class="pre">t</span></code>’ or ‘<code class="docutils literal notranslate"><span class="pre">b</span></code>’, so ‘<code class="docutils literal notranslate"><span class="pre">fr</span></code>’,
‘<code class="docutils literal notranslate"><span class="pre">rf</span></code>’, ‘<code class="docutils literal notranslate"><span class="pre">tr</span></code>’, ‘<code class="docutils literal notranslate"><span class="pre">rt</span></code>’, ‘<code class="docutils literal notranslate"><span class="pre">br</span></code>’, and ‘<code class="docutils literal notranslate"><span class="pre">rb</span></code>’ are also valid prefixes.</p>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.3: </span>The <code class="docutils literal notranslate"><span class="pre">'rb'</span></code> prefix of raw bytes literals has been added as a synonym
of <code class="docutils literal notranslate"><span class="pre">'br'</span></code>.</p>
<p>Support for the unicode legacy literal (<code class="docutils literal notranslate"><span class="pre">u'value'</span></code>) was reintroduced
to simplify the maintenance of dual Python 2.x and 3.x codebases.
See <span class="target" id="index-19"></span><a class="pep reference external" href="https://peps.python.org/pep-0414/"><strong>PEP 414</strong></a> for more information.</p>
</div>
</section>
<section id="formal-grammar">
<h3><span class="section-number">2.5.3. </span>Formal grammar<a class="headerlink" href="#formal-grammar" title="Link to this heading">¶</a></h3>
<p>String literals, except <a class="reference internal" href="#f-strings"><span class="std std-ref">“f-strings”</span></a> and
<a class="reference internal" href="#t-strings"><span class="std std-ref">“t-strings”</span></a>, are described by the
following lexical definitions.</p>
<p>These definitions use <a class="reference internal" href="introduction.html#lexical-lookaheads"><span class="std std-ref">negative lookaheads</span></a> (<code class="docutils literal notranslate"><span class="pre">!</span></code>)
to indicate that an ending quote ends the literal.</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-STRING">STRING</strong>:          [<a class="reference internal" href="#grammar-token-python-grammar-stringprefix"><code class="xref docutils literal notranslate"><span class="pre">stringprefix</span></code></a>] (<a class="reference internal" href="#grammar-token-python-grammar-stringcontent"><code class="xref docutils literal notranslate"><span class="pre">stringcontent</span></code></a>)
<strong id="grammar-token-python-grammar-stringprefix">stringprefix</strong>:    &lt;(<span class="sx">&quot;r&quot;</span> | <span class="sx">&quot;u&quot;</span> | <span class="sx">&quot;b&quot;</span> | <span class="sx">&quot;br&quot;</span> | <span class="sx">&quot;rb&quot;</span>), case-insensitive&gt;
<strong id="grammar-token-python-grammar-stringcontent">stringcontent</strong>:
   | <span class="sx">&quot;'''&quot;</span> ( !<span class="sx">&quot;'''&quot;</span> <a class="reference internal" href="#grammar-token-python-grammar-longstringitem"><code class="xref docutils literal notranslate"><span class="pre">longstringitem</span></code></a>)* <span class="sx">&quot;'''&quot;</span>
   | <span class="sx">'&quot;&quot;&quot;'</span> ( !<span class="sx">'&quot;&quot;&quot;'</span> <a class="reference internal" href="#grammar-token-python-grammar-longstringitem"><code class="xref docutils literal notranslate"><span class="pre">longstringitem</span></code></a>)* <span class="sx">'&quot;&quot;&quot;'</span>
   | <span class="sx">&quot;'&quot;</span> ( !<span class="sx">&quot;'&quot;</span> <a class="reference internal" href="#grammar-token-python-grammar-stringitem"><code class="xref docutils literal notranslate"><span class="pre">stringitem</span></code></a>)* <span class="sx">&quot;'&quot;</span>
   | <span class="sx">'&quot;'</span> ( !<span class="sx">'&quot;'</span> <a class="reference internal" href="#grammar-token-python-grammar-stringitem"><code class="xref docutils literal notranslate"><span class="pre">stringitem</span></code></a>)* <span class="sx">'&quot;'</span>
<strong id="grammar-token-python-grammar-stringitem">stringitem</strong>:      <a class="reference internal" href="#grammar-token-python-grammar-stringchar"><code class="xref docutils literal notranslate"><span class="pre">stringchar</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-stringescapeseq"><code class="xref docutils literal notranslate"><span class="pre">stringescapeseq</span></code></a>
<strong id="grammar-token-python-grammar-stringchar">stringchar</strong>:      &lt;any <a class="reference internal" href="#grammar-token-python-grammar-source_character"><code class="xref docutils literal notranslate"><span class="pre">source_character</span></code></a>, except backslash and newline&gt;
<strong id="grammar-token-python-grammar-longstringitem">longstringitem</strong>:  <a class="reference internal" href="#grammar-token-python-grammar-stringitem"><code class="xref docutils literal notranslate"><span class="pre">stringitem</span></code></a> | newline
<strong id="grammar-token-python-grammar-stringescapeseq">stringescapeseq</strong>: <span class="sx">&quot;\&quot;</span> &lt;any <a class="reference internal" href="#grammar-token-python-grammar-source_character"><code class="xref docutils literal notranslate"><span class="pre">source_character</span></code></a>&gt;
</pre>
<p>Note that as in all lexical definitions, whitespace is significant.
In particular, the prefix (if any) must be immediately followed by the starting
quote.</p>
</section>
<section id="escape-sequences">
<span id="index-20"></span><span id="id12"></span><h3><span class="section-number">2.5.4. </span>Escape sequences<a class="headerlink" href="#escape-sequences" title="Link to this heading">¶</a></h3>
<p>Unless an ‘<code class="docutils literal notranslate"><span class="pre">r</span></code>’ or ‘<code class="docutils literal notranslate"><span class="pre">R</span></code>’ prefix is present, escape sequences in string and
bytes literals are interpreted according to rules similar to those used by
Standard C.  The recognized escape sequences are:</p>
<table class="docutils align-default">
<thead>
<tr class="row-odd"><th class="head"><p>Escape Sequence</p></th>
<th class="head"><p>Meaning</p></th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">\</span></code>&lt;newline&gt;</p></td>
<td><p><a class="reference internal" href="#string-escape-ignore"><span class="std std-ref">Ignored end of line</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">\\</span></code></p></td>
<td><p><a class="reference internal" href="#string-escape-escaped-char"><span class="std std-ref">Backslash</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">\'</span></code></p></td>
<td><p><a class="reference internal" href="#string-escape-escaped-char"><span class="std std-ref">Single quote</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">\&quot;</span></code></p></td>
<td><p><a class="reference internal" href="#string-escape-escaped-char"><span class="std std-ref">Double quote</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">\a</span></code></p></td>
<td><p>ASCII Bell (BEL)</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">\b</span></code></p></td>
<td><p>ASCII Backspace (BS)</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">\f</span></code></p></td>
<td><p>ASCII Formfeed (FF)</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">\n</span></code></p></td>
<td><p>ASCII Linefeed (LF)</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">\r</span></code></p></td>
<td><p>ASCII Carriage Return (CR)</p></td>
</tr>
<tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">\t</span></code></p></td>
<td><p>ASCII Horizontal Tab (TAB)</p></td>
</tr>
<tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">\v</span></code></p></td>
<td><p>ASCII Vertical Tab (VT)</p></td>
</tr>
<tr class="row-odd"><td><p><code class="samp docutils literal notranslate"><span class="pre">\</span><em><span class="pre">ooo</span></em></code></p></td>
<td><p><a class="reference internal" href="#string-escape-oct"><span class="std std-ref">Octal character</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="samp docutils literal notranslate"><span class="pre">\x</span><em><span class="pre">hh</span></em></code></p></td>
<td><p><a class="reference internal" href="#string-escape-hex"><span class="std std-ref">Hexadecimal character</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="samp docutils literal notranslate"><span class="pre">\N{</span><em><span class="pre">name</span></em><span class="pre">}</span></code></p></td>
<td><p><a class="reference internal" href="#string-escape-named"><span class="std std-ref">Named Unicode character</span></a></p></td>
</tr>
<tr class="row-even"><td><p><code class="samp docutils literal notranslate"><span class="pre">\u</span><em><span class="pre">xxxx</span></em></code></p></td>
<td><p><a class="reference internal" href="#string-escape-long-hex"><span class="std std-ref">Hexadecimal Unicode character</span></a></p></td>
</tr>
<tr class="row-odd"><td><p><code class="samp docutils literal notranslate"><span class="pre">\U</span><em><span class="pre">xxxxxxxx</span></em></code></p></td>
<td><p><a class="reference internal" href="#string-escape-long-hex"><span class="std std-ref">Hexadecimal Unicode character</span></a></p></td>
</tr>
</tbody>
</table>
<section id="ignored-end-of-line">
<span id="string-escape-ignore"></span><h4><span class="section-number">2.5.4.1. </span>Ignored end of line<a class="headerlink" href="#ignored-end-of-line" title="Link to this heading">¶</a></h4>
<p>A backslash can be added at the end of a line to ignore the newline:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;This string will not include </span><span class="se">\</span>
<span class="gp">... </span><span class="s1">backslashes or newline characters.&#39;</span>
<span class="go">&#39;This string will not include backslashes or newline characters.&#39;</span>
</pre></div>
</div>
<p>The same result can be achieved using <a class="reference internal" href="#strings"><span class="std std-ref">triple-quoted strings</span></a>,
or parentheses and <a class="reference internal" href="expressions.html#string-concatenation"><span class="std std-ref">string literal concatenation</span></a>.</p>
</section>
<section id="escaped-characters">
<span id="string-escape-escaped-char"></span><h4><span class="section-number">2.5.4.2. </span>Escaped characters<a class="headerlink" href="#escaped-characters" title="Link to this heading">¶</a></h4>
<p>To include a backslash in a non-<a class="reference internal" href="#raw-strings"><span class="std std-ref">raw</span></a> Python string
literal, it must be doubled. The <code class="docutils literal notranslate"><span class="pre">\\</span></code> escape sequence denotes a single
backslash character:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="s1">&#39;C:</span><span class="se">\\</span><span class="s1">Program Files&#39;</span><span class="p">)</span>
<span class="go">C:\Program Files</span>
</pre></div>
</div>
<p>Similarly, the <code class="docutils literal notranslate"><span class="pre">\'</span></code> and <code class="docutils literal notranslate"><span class="pre">\&quot;</span></code> sequences denote the single and double
quote character, respectively:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="s1">&#39;</span><span class="se">\&#39;</span><span class="s1"> and </span><span class="se">\&quot;</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="go">&#39; and &quot;</span>
</pre></div>
</div>
</section>
<section id="octal-character">
<span id="string-escape-oct"></span><h4><span class="section-number">2.5.4.3. </span>Octal character<a class="headerlink" href="#octal-character" title="Link to this heading">¶</a></h4>
<p>The sequence <code class="samp docutils literal notranslate"><span class="pre">\</span><em><span class="pre">ooo</span></em></code> denotes a <em>character</em> with the octal (base 8)
value <em>ooo</em>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="se">\120</span><span class="s1">&#39;</span>
<span class="go">&#39;P&#39;</span>
</pre></div>
</div>
<p>Up to three octal digits (0 through 7) are accepted.</p>
<p>In a bytes literal, <em>character</em> means a <em>byte</em> with the given value.
In a string literal, it means a Unicode character with the given value.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.11: </span>Octal escapes with value larger than <code class="docutils literal notranslate"><span class="pre">0o377</span></code> (255) produce a
<a class="reference internal" href="../library/exceptions.html#DeprecationWarning" title="DeprecationWarning"><code class="xref py py-exc docutils literal notranslate"><span class="pre">DeprecationWarning</span></code></a>.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.12: </span>Octal escapes with value larger than <code class="docutils literal notranslate"><span class="pre">0o377</span></code> (255) produce a
<a class="reference internal" href="../library/exceptions.html#SyntaxWarning" title="SyntaxWarning"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SyntaxWarning</span></code></a>.
In a future Python version they will raise a <a class="reference internal" href="../library/exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SyntaxError</span></code></a>.</p>
</div>
</section>
<section id="hexadecimal-character">
<span id="string-escape-hex"></span><h4><span class="section-number">2.5.4.4. </span>Hexadecimal character<a class="headerlink" href="#hexadecimal-character" title="Link to this heading">¶</a></h4>
<p>The sequence <code class="samp docutils literal notranslate"><span class="pre">\x</span><em><span class="pre">hh</span></em></code> denotes a <em>character</em> with the hex (base 16)
value <em>hh</em>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="se">\x50</span><span class="s1">&#39;</span>
<span class="go">&#39;P&#39;</span>
</pre></div>
</div>
<p>Unlike in Standard C, exactly two hex digits are required.</p>
<p>In a bytes literal, <em>character</em> means a <em>byte</em> with the given value.
In a string literal, it means a Unicode character with the given value.</p>
</section>
<section id="named-unicode-character">
<span id="string-escape-named"></span><h4><span class="section-number">2.5.4.5. </span>Named Unicode character<a class="headerlink" href="#named-unicode-character" title="Link to this heading">¶</a></h4>
<p>The sequence <code class="samp docutils literal notranslate"><span class="pre">\N{</span><em><span class="pre">name</span></em><span class="pre">}</span></code> denotes a Unicode character
with the given <em>name</em>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="se">\N{LATIN CAPITAL LETTER P}</span><span class="s1">&#39;</span>
<span class="go">&#39;P&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="se">\N{SNAKE}</span><span class="s1">&#39;</span>
<span class="go">&#39;🐍&#39;</span>
</pre></div>
</div>
<p>This sequence cannot appear in <a class="reference internal" href="#bytes-literal"><span class="std std-ref">bytes literals</span></a>.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.3: </span>Support for <a class="reference external" href="https://www.unicode.org/Public/16.0.0/ucd/NameAliases.txt">name aliases</a>
has been added.</p>
</div>
</section>
<section id="hexadecimal-unicode-characters">
<span id="string-escape-long-hex"></span><h4><span class="section-number">2.5.4.6. </span>Hexadecimal Unicode characters<a class="headerlink" href="#hexadecimal-unicode-characters" title="Link to this heading">¶</a></h4>
<p>These sequences <code class="samp docutils literal notranslate"><span class="pre">\u</span><em><span class="pre">xxxx</span></em></code> and <code class="samp docutils literal notranslate"><span class="pre">\U</span><em><span class="pre">xxxxxxxx</span></em></code> denote the
Unicode character with the given hex (base 16) value.
Exactly four digits are required for <code class="docutils literal notranslate"><span class="pre">\u</span></code>; exactly eight digits are
required for <code class="docutils literal notranslate"><span class="pre">\U</span></code>.
The latter can encode any Unicode character.</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="se">\u1234</span><span class="s1">&#39;</span>
<span class="go">&#39;ሴ&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="s1">&#39;</span><span class="se">\U0001f40d</span><span class="s1">&#39;</span>
<span class="go">&#39;🐍&#39;</span>
</pre></div>
</div>
<p>These sequences cannot appear in <a class="reference internal" href="#bytes-literal"><span class="std std-ref">bytes literals</span></a>.</p>
</section>
<section id="unrecognized-escape-sequences">
<span id="index-21"></span><h4><span class="section-number">2.5.4.7. </span>Unrecognized escape sequences<a class="headerlink" href="#unrecognized-escape-sequences" title="Link to this heading">¶</a></h4>
<p>Unlike in Standard C, all unrecognized escape sequences are left in the string
unchanged, that is, <em>the backslash is left in the result</em>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="s1">&#39;\q&#39;</span><span class="p">)</span>
<span class="go">\q</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">list</span><span class="p">(</span><span class="s1">&#39;\q&#39;</span><span class="p">)</span>
<span class="go">[&#39;\\&#39;, &#39;q&#39;]</span>
</pre></div>
</div>
<p>Note that for bytes literals, the escape sequences only recognized in string
literals (<code class="docutils literal notranslate"><span class="pre">\N...</span></code>, <code class="docutils literal notranslate"><span class="pre">\u...</span></code>, <code class="docutils literal notranslate"><span class="pre">\U...</span></code>) fall into the category of
unrecognized escapes.</p>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.6: </span>Unrecognized escape sequences produce a <a class="reference internal" href="../library/exceptions.html#DeprecationWarning" title="DeprecationWarning"><code class="xref py py-exc docutils literal notranslate"><span class="pre">DeprecationWarning</span></code></a>.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.12: </span>Unrecognized escape sequences produce a <a class="reference internal" href="../library/exceptions.html#SyntaxWarning" title="SyntaxWarning"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SyntaxWarning</span></code></a>.
In a future Python version they will raise a <a class="reference internal" href="../library/exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">SyntaxError</span></code></a>.</p>
</div>
</section>
</section>
<section id="bytes-literals">
<span id="bytes-literal"></span><span id="index-22"></span><h3><span class="section-number">2.5.5. </span>Bytes literals<a class="headerlink" href="#bytes-literals" title="Link to this heading">¶</a></h3>
<p><em class="dfn">Bytes literals</em> are always prefixed with ‘<code class="docutils literal notranslate"><span class="pre">b</span></code>’ or ‘<code class="docutils literal notranslate"><span class="pre">B</span></code>’; they produce an
instance of the <a class="reference internal" href="../library/stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> type instead of the <a class="reference internal" href="../library/stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate"><span class="pre">str</span></code></a> type.
They may only contain ASCII characters; bytes with a numeric value of 128
or greater must be expressed with escape sequences (typically
<a class="reference internal" href="#string-escape-hex"><span class="std std-ref">Hexadecimal character</span></a> or <a class="reference internal" href="#string-escape-oct"><span class="std std-ref">Octal character</span></a>):</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="sa">b</span><span class="s1">&#39;</span><span class="se">\x89</span><span class="s1">PNG</span><span class="se">\r\n\x1a\n</span><span class="s1">&#39;</span>
<span class="go">b&#39;\x89PNG\r\n\x1a\n&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">list</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;</span><span class="se">\x89</span><span class="s1">PNG</span><span class="se">\r\n\x1a\n</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="go">[137, 80, 78, 71, 13, 10, 26, 10]</span>
</pre></div>
</div>
<p>Similarly, a zero byte must be expressed using an escape sequence (typically
<code class="docutils literal notranslate"><span class="pre">\0</span></code> or <code class="docutils literal notranslate"><span class="pre">\x00</span></code>).</p>
</section>
<section id="raw-string-literals">
<span id="raw-strings"></span><span id="index-23"></span><h3><span class="section-number">2.5.6. </span>Raw string literals<a class="headerlink" href="#raw-string-literals" title="Link to this heading">¶</a></h3>
<p>Both string and bytes literals may optionally be prefixed with a letter ‘<code class="docutils literal notranslate"><span class="pre">r</span></code>’
or ‘<code class="docutils literal notranslate"><span class="pre">R</span></code>’; such constructs are called <em class="dfn">raw string literals</em>
and <em class="dfn">raw bytes literals</em> respectively and treat backslashes as
literal characters.
As a result, in raw string literals, <a class="reference internal" href="#escape-sequences"><span class="std std-ref">escape sequences</span></a>
are not treated specially:</p>
<div class="highlight-pycon notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="sa">r</span><span class="s1">&#39;\d</span><span class="si">{4}</span><span class="s1">-\d</span><span class="si">{2}</span><span class="s1">-\d</span><span class="si">{2}</span><span class="s1">&#39;</span>
<span class="go">&#39;\\d{4}-\\d{2}-\\d{2}&#39;</span>
</pre></div>
</div>
<p>Even in a raw literal, quotes can be escaped with a backslash, but the
backslash remains in the result; for example, <code class="docutils literal notranslate"><span class="pre">r&quot;\&quot;&quot;</span></code> is a valid string
literal consisting of two characters: a backslash and a double quote; <code class="docutils literal notranslate"><span class="pre">r&quot;\&quot;</span></code>
is not a valid string literal (even a raw string cannot end in an odd number of
backslashes).  Specifically, <em>a raw literal cannot end in a single backslash</em>
(since the backslash would escape the following quote character).  Note also
that a single backslash followed by a newline is interpreted as those two
characters as part of the literal, <em>not</em> as a line continuation.</p>
</section>
<section id="formatted-string-literals">
<span id="f-strings"></span><span id="index-24"></span><span id="id13"></span><h3><span class="section-number">2.5.7. </span>f-strings<a class="headerlink" href="#formatted-string-literals" title="Link to this heading">¶</a></h3>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.6.</span></p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.7: </span>The <a class="reference internal" href="expressions.html#await"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">await</span></code></a> and <a class="reference internal" href="compound_stmts.html#async-for"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">async</span> <span class="pre">for</span></code></a> can be used in expressions
within f-strings.</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.8: </span>Added the debug specifier (<code class="docutils literal notranslate"><span class="pre">=</span></code>)</p>
</div>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.12: </span>Many restrictions on expressions within f-strings have been removed.
Notably, nested strings, comments, and backslashes are now permitted.</p>
</div>
<p>A <em class="dfn">formatted string literal</em> or <em class="dfn">f-string</em> is a string literal
that is prefixed with ‘<code class="docutils literal notranslate"><span class="pre">f</span></code>’ or ‘<code class="docutils literal notranslate"><span class="pre">F</span></code>’.
Unlike other string literals, f-strings do not have a constant value.
They may contain <em>replacement fields</em> delimited by curly braces <code class="docutils literal notranslate"><span class="pre">{}</span></code>.
Replacement fields contain expressions which are evaluated at run time.
For example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">who</span> <span class="o">=</span> <span class="s1">&#39;nobody&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">nationality</span> <span class="o">=</span> <span class="s1">&#39;Spanish&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">who</span><span class="o">.</span><span class="n">title</span><span class="p">()</span><span class="si">}</span><span class="s1"> expects the </span><span class="si">{</span><span class="n">nationality</span><span class="si">}</span><span class="s1"> Inquisition!&#39;</span>
<span class="go">&#39;Nobody expects the Spanish Inquisition!&#39;</span>
</pre></div>
</div>
<p>Any doubled curly braces (<code class="docutils literal notranslate"><span class="pre">{{</span></code> or <code class="docutils literal notranslate"><span class="pre">}}</span></code>) outside replacement fields
are replaced with the corresponding single curly brace:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;</span><span class="se">{{</span><span class="s1">...</span><span class="se">}}</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="go">{...}</span>
</pre></div>
</div>
<p>Other characters outside replacement fields are treated like in ordinary
string literals.
This means that escape sequences are decoded (except when a literal is
also marked as a raw string), and newlines are possible in triple-quoted
f-strings:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">name</span> <span class="o">=</span> <span class="s1">&#39;Galahad&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">favorite_color</span> <span class="o">=</span> <span class="s1">&#39;blue&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s1">:</span><span class="se">\t</span><span class="si">{</span><span class="n">favorite_color</span><span class="si">}</span><span class="s1">&#39;</span><span class="p">)</span>
<span class="go">Galahad:       blue</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="sa">rf</span><span class="s2">&quot;C:\Users\</span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="go">C:\Users\Galahad</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s1">&#39;&#39;&#39;Three shall be the number of the counting</span>
<span class="gp">... </span><span class="s1">and the number of the counting shall be three.&#39;&#39;&#39;</span><span class="p">)</span>
<span class="go">Three shall be the number of the counting</span>
<span class="go">and the number of the counting shall be three.</span>
</pre></div>
</div>
<p>Expressions in formatted string literals are treated like regular
Python expressions.
Each expression is evaluated in the context where the formatted string literal
appears, in order from left to right.
An empty expression is not allowed, and both <a class="reference internal" href="expressions.html#lambda"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">lambda</span></code></a> and
assignment expressions <code class="docutils literal notranslate"><span class="pre">:=</span></code> must be surrounded by explicit parentheses:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="p">(</span><span class="n">half</span><span class="w"> </span><span class="o">:=</span><span class="w"> </span><span class="mi">1</span><span class="o">/</span><span class="mi">2</span><span class="p">)</span><span class="si">}</span><span class="s1">, </span><span class="si">{</span><span class="n">half</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">42</span><span class="si">}</span><span class="s1">&#39;</span>
<span class="go">&#39;0.5, 21.0&#39;</span>
</pre></div>
</div>
<p>Reusing the outer f-string quoting type inside a replacement field is
permitted:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">a</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">(</span><span class="n">x</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span>
<span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s2">&quot;abc </span><span class="si">{</span><span class="n">a</span><span class="p">[</span><span class="s2">&quot;x&quot;</span><span class="p">]</span><span class="si">}</span><span class="s2"> def&quot;</span>
<span class="go">&#39;abc 2 def&#39;</span>
</pre></div>
</div>
<p>Backslashes are also allowed in replacement fields and are evaluated the same
way as in any other context:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">a</span> <span class="o">=</span> <span class="p">[</span><span class="s2">&quot;a&quot;</span><span class="p">,</span> <span class="s2">&quot;b&quot;</span><span class="p">,</span> <span class="s2">&quot;c&quot;</span><span class="p">]</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;List a contains:</span><span class="se">\n</span><span class="si">{</span><span class="s2">&quot;</span><span class="se">\n</span><span class="s2">&quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">a</span><span class="p">)</span><span class="si">}</span><span class="s2">&quot;</span><span class="p">)</span>
<span class="go">List a contains:</span>
<span class="go">a</span>
<span class="go">b</span>
<span class="go">c</span>
</pre></div>
</div>
<p>It is possible to nest f-strings:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">name</span> <span class="o">=</span> <span class="s1">&#39;world&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s1">&#39;Repeated:</span><span class="si">{</span><span class="sa">f</span><span class="s1">&#39; hello </span><span class="si">{</span><span class="n">name</span><span class="si">}</span><span class="s1">&#39;</span><span class="w"> </span><span class="o">*</span><span class="w"> </span><span class="mi">3</span><span class="si">}</span><span class="s1">&#39;</span>
<span class="go">&#39;Repeated: hello world hello world hello world&#39;</span>
</pre></div>
</div>
<p>Portable Python programs should not use more than 5 levels of nesting.</p>
<div class="impl-detail compound">
<p><strong>CPython implementation detail:</strong> CPython does not limit nesting of f-strings.</p>
</div>
<p>Replacement expressions can contain newlines in both single-quoted and
triple-quoted f-strings and they can contain comments.
Everything that comes after a <code class="docutils literal notranslate"><span class="pre">#</span></code> inside a replacement field
is a comment (even closing braces and quotes).
This means that replacement fields with comments must be closed in a
different line:</p>
<div class="highlight-text notranslate"><div class="highlight"><pre><span></span>&gt;&gt;&gt; a = 2
&gt;&gt;&gt; f&quot;abc{a  # This comment  }&quot;  continues until the end of the line
...       + 3}&quot;
&#39;abc5&#39;
</pre></div>
</div>
<p>After the expression, replacement fields may optionally contain:</p>
<ul class="simple">
<li><p>a <em>debug specifier</em> – an equal sign (<code class="docutils literal notranslate"><span class="pre">=</span></code>), optionally surrounded by
whitespace on one or both sides;</p></li>
<li><p>a <em>conversion specifier</em> – <code class="docutils literal notranslate"><span class="pre">!s</span></code>, <code class="docutils literal notranslate"><span class="pre">!r</span></code> or <code class="docutils literal notranslate"><span class="pre">!a</span></code>; and/or</p></li>
<li><p>a <em>format specifier</em> prefixed with a colon (<code class="docutils literal notranslate"><span class="pre">:</span></code>).</p></li>
</ul>
<p>See the <a class="reference internal" href="../library/stdtypes.html#stdtypes-fstrings"><span class="std std-ref">Standard Library section on f-strings</span></a>
for details on how these fields are evaluated.</p>
<p>As that section explains, <em>format specifiers</em> are passed as the second argument
to the <a class="reference internal" href="../library/functions.html#format" title="format"><code class="xref py py-func docutils literal notranslate"><span class="pre">format()</span></code></a> function to format a replacement field value.
For example, they can be used to specify a field width and padding characters
using the <a class="reference internal" href="../library/string.html#formatspec"><span class="std std-ref">Format Specification Mini-Language</span></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">number</span> <span class="o">=</span> <span class="mf">14.3</span>
<span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">number</span><span class="si">:</span><span class="s1">20.7f</span><span class="si">}</span><span class="s1">&#39;</span>
<span class="go">&#39;          14.3000000&#39;</span>
</pre></div>
</div>
<p>Top-level format specifiers may include nested replacement fields:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">field_size</span> <span class="o">=</span> <span class="mi">20</span>
<span class="gp">&gt;&gt;&gt; </span><span class="n">precision</span> <span class="o">=</span> <span class="mi">7</span>
<span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">number</span><span class="si">:{</span><span class="n">field_size</span><span class="si">}</span><span class="s1">.</span><span class="si">{</span><span class="n">precision</span><span class="si">}</span><span class="s1">f</span><span class="si">}</span><span class="s1">&#39;</span>
<span class="go">&#39;          14.3000000&#39;</span>
</pre></div>
</div>
<p>These nested fields may include their own conversion fields and
<a class="reference internal" href="../library/string.html#formatspec"><span class="std std-ref">format specifiers</span></a>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">number</span> <span class="o">=</span> <span class="mi">3</span>
<span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">number</span><span class="si">:{</span><span class="n">field_size</span><span class="si">}}</span><span class="s1">&#39;</span>
<span class="go">&#39;                   3&#39;</span>
<span class="gp">&gt;&gt;&gt; </span><span class="sa">f</span><span class="s1">&#39;</span><span class="si">{</span><span class="n">number</span><span class="si">:{</span><span class="n">field_size</span><span class="si">:</span><span class="s1">05</span><span class="se">}}</span><span class="s1">&#39;</span>
<span class="go">&#39;00000000000000000003&#39;</span>
</pre></div>
</div>
<p>However, these nested fields may not include more deeply nested replacement
fields.</p>
<p>Formatted string literals cannot be used as <a class="reference internal" href="../glossary.html#term-docstring"><span class="xref std std-term">docstrings</span></a>,
even if they do not include expressions:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="k">def</span><span class="w"> </span><span class="nf">foo</span><span class="p">():</span>
<span class="gp">... </span>    <span class="sa">f</span><span class="s2">&quot;Not a docstring&quot;</span>
<span class="gp">...</span>
<span class="gp">&gt;&gt;&gt; </span><span class="nb">print</span><span class="p">(</span><span class="n">foo</span><span class="o">.</span><span class="vm">__doc__</span><span class="p">)</span>
<span class="go">None</span>
</pre></div>
</div>
<div class="admonition seealso">
<p class="admonition-title">See also</p>
<ul class="simple">
<li><p><span class="target" id="index-25"></span><a class="pep reference external" href="https://peps.python.org/pep-0498/"><strong>PEP 498</strong></a> – Literal String Interpolation</p></li>
<li><p><span class="target" id="index-26"></span><a class="pep reference external" href="https://peps.python.org/pep-0701/"><strong>PEP 701</strong></a> – Syntactic formalization of f-strings</p></li>
<li><p><a class="reference internal" href="../library/stdtypes.html#str.format" title="str.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">str.format()</span></code></a>, which uses a related format string mechanism.</p></li>
</ul>
</div>
</section>
<section id="template-string-literals">
<span id="t-strings"></span><span id="id14"></span><h3><span class="section-number">2.5.8. </span>t-strings<a class="headerlink" href="#template-string-literals" title="Link to this heading">¶</a></h3>
<div class="versionadded">
<p><span class="versionmodified added">Added in version 3.14.</span></p>
</div>
<p>A <em class="dfn">template string literal</em> or <em class="dfn">t-string</em> is a string literal
that is prefixed with ‘<code class="docutils literal notranslate"><span class="pre">t</span></code>’ or ‘<code class="docutils literal notranslate"><span class="pre">T</span></code>’.
These strings follow the same syntax rules as
<a class="reference internal" href="#f-strings"><span class="std std-ref">formatted string literals</span></a>.
For differences in evaluation rules, see the
<a class="reference internal" href="../library/stdtypes.html#stdtypes-tstrings"><span class="std std-ref">Standard Library section on t-strings</span></a></p>
</section>
<section id="formal-grammar-for-f-strings">
<h3><span class="section-number">2.5.9. </span>Formal grammar for f-strings<a class="headerlink" href="#formal-grammar-for-f-strings" title="Link to this heading">¶</a></h3>
<p>F-strings are handled partly by the <a class="reference internal" href="../glossary.html#term-lexical-analyzer"><span class="xref std std-term">lexical analyzer</span></a>, which produces the
tokens <a class="reference internal" href="../library/token.html#token.FSTRING_START" title="token.FSTRING_START"><code class="xref py py-data docutils literal notranslate"><span class="pre">FSTRING_START</span></code></a>, <a class="reference internal" href="../library/token.html#token.FSTRING_MIDDLE" title="token.FSTRING_MIDDLE"><code class="xref py py-data docutils literal notranslate"><span class="pre">FSTRING_MIDDLE</span></code></a>
and <a class="reference internal" href="../library/token.html#token.FSTRING_END" title="token.FSTRING_END"><code class="xref py py-data docutils literal notranslate"><span class="pre">FSTRING_END</span></code></a>, and partly by the parser, which handles
expressions in the replacement field.
The exact way the work is split is a CPython implementation detail.</p>
<p>Correspondingly, the f-string grammar is a mix of
<a class="reference internal" href="introduction.html#notation-lexical-vs-syntactic"><span class="std std-ref">lexical and syntactic definitions</span></a>.</p>
<p>Whitespace is significant in these situations:</p>
<ul>
<li><p>There may be no whitespace in <a class="reference internal" href="../library/token.html#token.FSTRING_START" title="token.FSTRING_START"><code class="xref py py-data docutils literal notranslate"><span class="pre">FSTRING_START</span></code></a> (between
the prefix and quote).</p></li>
<li><p>Whitespace in <a class="reference internal" href="../library/token.html#token.FSTRING_MIDDLE" title="token.FSTRING_MIDDLE"><code class="xref py py-data docutils literal notranslate"><span class="pre">FSTRING_MIDDLE</span></code></a> is part of the literal
string contents.</p></li>
<li><p>In <code class="docutils literal notranslate"><span class="pre">fstring_replacement_field</span></code>, if <code class="docutils literal notranslate"><span class="pre">f_debug_specifier</span></code> is present,
all whitespace after the opening brace until the <code class="docutils literal notranslate"><span class="pre">f_debug_specifier</span></code>,
as well as whitespace immediately following <code class="docutils literal notranslate"><span class="pre">f_debug_specifier</span></code>,
is retained as part of the expression.</p>
<div class="impl-detail compound">
<p><strong>CPython implementation detail:</strong> The expression is not handled in the tokenization phase; it is
retrieved from the source code using locations of the <code class="docutils literal notranslate"><span class="pre">{</span></code> token
and the token after <code class="docutils literal notranslate"><span class="pre">=</span></code>.</p>
</div>
</li>
</ul>
<p>The <code class="docutils literal notranslate"><span class="pre">FSTRING_MIDDLE</span></code> definition uses
<a class="reference internal" href="introduction.html#lexical-lookaheads"><span class="std std-ref">negative lookaheads</span></a> (<code class="docutils literal notranslate"><span class="pre">!</span></code>)
to indicate special characters (backslash, newline, <code class="docutils literal notranslate"><span class="pre">{</span></code>, <code class="docutils literal notranslate"><span class="pre">}</span></code>) and
sequences (<code class="docutils literal notranslate"><span class="pre">f_quote</span></code>).</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-fstring">fstring</strong>:    <a class="reference internal" href="#grammar-token-python-grammar-FSTRING_START"><code class="xref docutils literal notranslate"><span class="pre">FSTRING_START</span></code></a> <a class="reference internal" href="#grammar-token-python-grammar-fstring_middle"><code class="xref docutils literal notranslate"><span class="pre">fstring_middle</span></code></a>* <a class="reference internal" href="#grammar-token-python-grammar-FSTRING_END"><code class="xref docutils literal notranslate"><span class="pre">FSTRING_END</span></code></a>

<strong id="grammar-token-python-grammar-FSTRING_START">FSTRING_START</strong>:      <a class="reference internal" href="#grammar-token-python-grammar-fstringprefix"><code class="xref docutils literal notranslate"><span class="pre">fstringprefix</span></code></a> (<span class="sx">&quot;'&quot;</span> | <span class="sx">'&quot;'</span> | <span class="sx">&quot;'''&quot;</span> | <span class="sx">'&quot;&quot;&quot;'</span>)
<strong id="grammar-token-python-grammar-FSTRING_END">FSTRING_END</strong>:        <a class="reference internal" href="#grammar-token-python-grammar-f_quote"><code class="xref docutils literal notranslate"><span class="pre">f_quote</span></code></a>
<strong id="grammar-token-python-grammar-fstringprefix">fstringprefix</strong>:      &lt;(<span class="sx">&quot;f&quot;</span> | <span class="sx">&quot;fr&quot;</span> | <span class="sx">&quot;rf&quot;</span>), case-insensitive&gt;
<strong id="grammar-token-python-grammar-f_debug_specifier">f_debug_specifier</strong>:  <span class="sx">'='</span>
<strong id="grammar-token-python-grammar-f_quote">f_quote</strong>:            &lt;the quote character(s) used in FSTRING_START&gt;

<strong id="grammar-token-python-grammar-fstring_middle">fstring_middle</strong>:
   | <a class="reference internal" href="#grammar-token-python-grammar-fstring_replacement_field"><code class="xref docutils literal notranslate"><span class="pre">fstring_replacement_field</span></code></a>
   | <a class="reference internal" href="#grammar-token-python-grammar-FSTRING_MIDDLE"><code class="xref docutils literal notranslate"><span class="pre">FSTRING_MIDDLE</span></code></a>
<strong id="grammar-token-python-grammar-FSTRING_MIDDLE">FSTRING_MIDDLE</strong>:
   | (!<span class="sx">&quot;\&quot;</span> !<a class="reference internal" href="#grammar-token-python-grammar-newline"><code class="xref docutils literal notranslate"><span class="pre">newline</span></code></a> !<span class="sx">'{'</span> !<span class="sx">'}'</span> !<a class="reference internal" href="#grammar-token-python-grammar-f_quote"><code class="xref docutils literal notranslate"><span class="pre">f_quote</span></code></a>) <a class="reference internal" href="#grammar-token-python-grammar-source_character"><code class="xref docutils literal notranslate"><span class="pre">source_character</span></code></a>
   | <a class="reference internal" href="#grammar-token-python-grammar-stringescapeseq"><code class="xref docutils literal notranslate"><span class="pre">stringescapeseq</span></code></a>
   | <span class="sx">&quot;{{&quot;</span>
   | <span class="sx">&quot;}}&quot;</span>
   | &lt;newline, in triple-quoted f-strings only&gt;
<strong id="grammar-token-python-grammar-fstring_replacement_field">fstring_replacement_field</strong>:
   | <span class="sx">'{'</span> <a class="reference internal" href="#grammar-token-python-grammar-f_expression"><code class="xref docutils literal notranslate"><span class="pre">f_expression</span></code></a> [<a class="reference internal" href="#grammar-token-python-grammar-f_debug_specifier"><code class="xref docutils literal notranslate"><span class="pre">f_debug_specifier</span></code></a>] [<a class="reference internal" href="#grammar-token-python-grammar-fstring_conversion"><code class="xref docutils literal notranslate"><span class="pre">fstring_conversion</span></code></a>]
         [<a class="reference internal" href="#grammar-token-python-grammar-fstring_full_format_spec"><code class="xref docutils literal notranslate"><span class="pre">fstring_full_format_spec</span></code></a>] <span class="sx">'}'</span>
<strong id="grammar-token-python-grammar-fstring_conversion">fstring_conversion</strong>:
   | <span class="sx">&quot;!&quot;</span> (<span class="sx">&quot;s&quot;</span> | <span class="sx">&quot;r&quot;</span> | <span class="sx">&quot;a&quot;</span>)
<strong id="grammar-token-python-grammar-fstring_full_format_spec">fstring_full_format_spec</strong>:
   | <span class="sx">':'</span> <a class="reference internal" href="#grammar-token-python-grammar-fstring_format_spec"><code class="xref docutils literal notranslate"><span class="pre">fstring_format_spec</span></code></a>*
<strong id="grammar-token-python-grammar-fstring_format_spec">fstring_format_spec</strong>:
   | <a class="reference internal" href="#grammar-token-python-grammar-FSTRING_MIDDLE"><code class="xref docutils literal notranslate"><span class="pre">FSTRING_MIDDLE</span></code></a>
   | <a class="reference internal" href="#grammar-token-python-grammar-fstring_replacement_field"><code class="xref docutils literal notranslate"><span class="pre">fstring_replacement_field</span></code></a>
<strong id="grammar-token-python-grammar-f_expression">f_expression</strong>:
   | <span class="sx">','</span>.(<a class="reference internal" href="expressions.html#grammar-token-python-grammar-conditional_expression"><code class="xref docutils literal notranslate"><span class="pre">conditional_expression</span></code></a> | <span class="sx">&quot;*&quot;</span> <a class="reference internal" href="expressions.html#grammar-token-python-grammar-or_expr"><code class="xref docutils literal notranslate"><span class="pre">or_expr</span></code></a>)+ [<span class="sx">&quot;,&quot;</span>]
   | <a class="reference internal" href="expressions.html#grammar-token-python-grammar-yield_expression"><code class="xref docutils literal notranslate"><span class="pre">yield_expression</span></code></a>
</pre>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>In the above grammar snippet, the <code class="docutils literal notranslate"><span class="pre">f_quote</span></code> and <code class="docutils literal notranslate"><span class="pre">FSTRING_MIDDLE</span></code> rules
are context-sensitive – they depend on the contents of <code class="docutils literal notranslate"><span class="pre">FSTRING_START</span></code>
of the nearest enclosing <code class="docutils literal notranslate"><span class="pre">fstring</span></code>.</p>
<p>Constructing a more traditional formal grammar from this template is left
as an exercise for the reader.</p>
</div>
<p>The grammar for t-strings is identical to the one for f-strings, with <em>t</em>
instead of <em>f</em> at the beginning of rule and token names and in the prefix.</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-tstring">tstring</strong>:    TSTRING_START tstring_middle* TSTRING_END

&lt;rest of the t-string grammar is omitted; see above&gt;
</pre>
</section>
</section>
<section id="numeric-literals">
<span id="numbers"></span><h2><span class="section-number">2.6. </span>Numeric literals<a class="headerlink" href="#numeric-literals" title="Link to this heading">¶</a></h2>
<p id="index-27"><a class="reference internal" href="../library/token.html#token.NUMBER" title="token.NUMBER"><code class="xref py py-data docutils literal notranslate"><span class="pre">NUMBER</span></code></a> tokens represent numeric literals, of which there are
three types: integers, floating-point numbers, and imaginary numbers.</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-NUMBER">NUMBER</strong>: <a class="reference internal" href="#grammar-token-python-grammar-integer"><code class="xref docutils literal notranslate"><span class="pre">integer</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-floatnumber"><code class="xref docutils literal notranslate"><span class="pre">floatnumber</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-imagnumber"><code class="xref docutils literal notranslate"><span class="pre">imagnumber</span></code></a>
</pre>
<p>The numeric value of a numeric literal is the same as if it were passed as a
string to the <a class="reference internal" href="../library/functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate"><span class="pre">int</span></code></a>, <a class="reference internal" href="../library/functions.html#float" title="float"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a> or <a class="reference internal" href="../library/functions.html#complex" title="complex"><code class="xref py py-class docutils literal notranslate"><span class="pre">complex</span></code></a> class
constructor, respectively.
Note that not all valid inputs for those constructors are also valid literals.</p>
<p>Numeric literals do not include a sign; a phrase like <code class="docutils literal notranslate"><span class="pre">-1</span></code> is
actually an expression composed of the unary operator ‘<code class="docutils literal notranslate"><span class="pre">-</span></code>’ and the literal
<code class="docutils literal notranslate"><span class="pre">1</span></code>.</p>
<section id="integer-literals">
<span id="integers"></span><span id="index-28"></span><h3><span class="section-number">2.6.1. </span>Integer literals<a class="headerlink" href="#integer-literals" title="Link to this heading">¶</a></h3>
<p>Integer literals denote whole numbers. For example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mi">7</span>
<span class="mi">3</span>
<span class="mi">2147483647</span>
</pre></div>
</div>
<p>There is no limit for the length of integer literals apart from what can be
stored in available memory:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mi">7922816251426433759354395033679228162514264337593543950336</span>
</pre></div>
</div>
<p>Underscores can be used to group digits for enhanced readability,
and are ignored for determining the numeric value of the literal.
For example, the following literals are equivalent:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mi">100_000_000_000</span>
<span class="mi">100000000000</span>
<span class="mi">1_00_00_00_00_000</span>
</pre></div>
</div>
<p>Underscores can only occur between digits.
For example, <code class="docutils literal notranslate"><span class="pre">_123</span></code>, <code class="docutils literal notranslate"><span class="pre">321_</span></code>, and <code class="docutils literal notranslate"><span class="pre">123__321</span></code> are <em>not</em> valid literals.</p>
<p>Integers can be specified in binary (base 2), octal (base 8), or hexadecimal
(base 16) using the prefixes <code class="docutils literal notranslate"><span class="pre">0b</span></code>, <code class="docutils literal notranslate"><span class="pre">0o</span></code> and <code class="docutils literal notranslate"><span class="pre">0x</span></code>, respectively.
Hexadecimal digits 10 through 15 are represented by letters <code class="docutils literal notranslate"><span class="pre">A</span></code>-<code class="docutils literal notranslate"><span class="pre">F</span></code>,
case-insensitive.  For example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mb">0b100110111</span>
<span class="mb">0b_1110_0101</span>
<span class="mo">0o177</span>
<span class="mo">0o377</span>
<span class="mh">0xdeadbeef</span>
<span class="mh">0xDead_Beef</span>
</pre></div>
</div>
<p>An underscore can follow the base specifier.
For example, <code class="docutils literal notranslate"><span class="pre">0x_1f</span></code> is a valid literal, but <code class="docutils literal notranslate"><span class="pre">0_x1f</span></code> and <code class="docutils literal notranslate"><span class="pre">0x__1f</span></code> are
not.</p>
<p>Leading zeros in a non-zero decimal number are not allowed.
For example, <code class="docutils literal notranslate"><span class="pre">0123</span></code> is not a valid literal.
This is for disambiguation with C-style octal literals, which Python used
before version 3.0.</p>
<p>Formally, integer literals are described by the following lexical definitions:</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-integer">integer</strong>:      <a class="reference internal" href="#grammar-token-python-grammar-decinteger"><code class="xref docutils literal notranslate"><span class="pre">decinteger</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-bininteger"><code class="xref docutils literal notranslate"><span class="pre">bininteger</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-octinteger"><code class="xref docutils literal notranslate"><span class="pre">octinteger</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-hexinteger"><code class="xref docutils literal notranslate"><span class="pre">hexinteger</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-zerointeger"><code class="xref docutils literal notranslate"><span class="pre">zerointeger</span></code></a>
<strong id="grammar-token-python-grammar-decinteger">decinteger</strong>:   <a class="reference internal" href="#grammar-token-python-grammar-nonzerodigit"><code class="xref docutils literal notranslate"><span class="pre">nonzerodigit</span></code></a> ([<span class="sx">&quot;_&quot;</span>] <a class="reference internal" href="#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a>)*
<strong id="grammar-token-python-grammar-bininteger">bininteger</strong>:   <span class="sx">&quot;0&quot;</span> (<span class="sx">&quot;b&quot;</span> | <span class="sx">&quot;B&quot;</span>) ([<span class="sx">&quot;_&quot;</span>] <a class="reference internal" href="#grammar-token-python-grammar-bindigit"><code class="xref docutils literal notranslate"><span class="pre">bindigit</span></code></a>)+
<strong id="grammar-token-python-grammar-octinteger">octinteger</strong>:   <span class="sx">&quot;0&quot;</span> (<span class="sx">&quot;o&quot;</span> | <span class="sx">&quot;O&quot;</span>) ([<span class="sx">&quot;_&quot;</span>] <a class="reference internal" href="#grammar-token-python-grammar-octdigit"><code class="xref docutils literal notranslate"><span class="pre">octdigit</span></code></a>)+
<strong id="grammar-token-python-grammar-hexinteger">hexinteger</strong>:   <span class="sx">&quot;0&quot;</span> (<span class="sx">&quot;x&quot;</span> | <span class="sx">&quot;X&quot;</span>) ([<span class="sx">&quot;_&quot;</span>] <a class="reference internal" href="#grammar-token-python-grammar-hexdigit"><code class="xref docutils literal notranslate"><span class="pre">hexdigit</span></code></a>)+
<strong id="grammar-token-python-grammar-zerointeger">zerointeger</strong>:  <span class="sx">&quot;0&quot;</span>+ ([<span class="sx">&quot;_&quot;</span>] <span class="sx">&quot;0&quot;</span>)*
<strong id="grammar-token-python-grammar-nonzerodigit">nonzerodigit</strong>: <span class="sx">&quot;1&quot;</span>...<span class="sx">&quot;9&quot;</span>
<strong id="grammar-token-python-grammar-digit">digit</strong>:        <span class="sx">&quot;0&quot;</span>...<span class="sx">&quot;9&quot;</span>
<strong id="grammar-token-python-grammar-bindigit">bindigit</strong>:     <span class="sx">&quot;0&quot;</span> | <span class="sx">&quot;1&quot;</span>
<strong id="grammar-token-python-grammar-octdigit">octdigit</strong>:     <span class="sx">&quot;0&quot;</span>...<span class="sx">&quot;7&quot;</span>
<strong id="grammar-token-python-grammar-hexdigit">hexdigit</strong>:     <a class="reference internal" href="#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a> | <span class="sx">&quot;a&quot;</span>...<span class="sx">&quot;f&quot;</span> | <span class="sx">&quot;A&quot;</span>...<span class="sx">&quot;F&quot;</span>
</pre>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.6: </span>Underscores are now allowed for grouping purposes in literals.</p>
</div>
</section>
<section id="floating-point-literals">
<span id="floating"></span><span id="index-29"></span><h3><span class="section-number">2.6.2. </span>Floating-point literals<a class="headerlink" href="#floating-point-literals" title="Link to this heading">¶</a></h3>
<p>Floating-point (float) literals, such as <code class="docutils literal notranslate"><span class="pre">3.14</span></code> or <code class="docutils literal notranslate"><span class="pre">1.5</span></code>, denote
<a class="reference internal" href="datamodel.html#datamodel-float"><span class="std std-ref">approximations of real numbers</span></a>.</p>
<p>They consist of <em>integer</em> and <em>fraction</em> parts, each composed of decimal digits.
The parts are separated by a decimal point, <code class="docutils literal notranslate"><span class="pre">.</span></code>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mf">2.71828</span>
<span class="mf">4.0</span>
</pre></div>
</div>
<p>Unlike in integer literals, leading zeros are allowed.
For example, <code class="docutils literal notranslate"><span class="pre">077.010</span></code> is legal, and denotes the same number as <code class="docutils literal notranslate"><span class="pre">77.01</span></code>.</p>
<p>As in integer literals, single underscores may occur between digits to help
readability:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mf">96_485.332_123</span>
<span class="mf">3.14_15_93</span>
</pre></div>
</div>
<p>Either of these parts, but not both, can be empty. For example:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mf">10.</span>  <span class="c1"># (equivalent to 10.0)</span>
<span class="mf">.001</span>  <span class="c1"># (equivalent to 0.001)</span>
</pre></div>
</div>
<p>Optionally, the integer and fraction may be followed by an <em>exponent</em>:
the letter <code class="docutils literal notranslate"><span class="pre">e</span></code> or <code class="docutils literal notranslate"><span class="pre">E</span></code>, followed by an optional sign, <code class="docutils literal notranslate"><span class="pre">+</span></code> or <code class="docutils literal notranslate"><span class="pre">-</span></code>,
and a number in the same format as the integer and fraction parts.
The <code class="docutils literal notranslate"><span class="pre">e</span></code> or <code class="docutils literal notranslate"><span class="pre">E</span></code> represents “times ten raised to the power of”:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mf">1.0e3</span>  <span class="c1"># (represents 1.0×10³, or 1000.0)</span>
<span class="mf">1.166e-5</span>  <span class="c1"># (represents 1.166×10⁻⁵, or 0.00001166)</span>
<span class="mf">6.02214076e+23</span>  <span class="c1"># (represents 6.02214076×10²³, or 602214076000000000000000.)</span>
</pre></div>
</div>
<p>In floats with only integer and exponent parts, the decimal point may be
omitted:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mf">1e3</span>  <span class="c1"># (equivalent to 1.e3 and 1.0e3)</span>
<span class="mf">0e0</span>  <span class="c1"># (equivalent to 0.)</span>
</pre></div>
</div>
<p>Formally, floating-point literals are described by the following
lexical definitions:</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-floatnumber">floatnumber</strong>:
   | <a class="reference internal" href="#grammar-token-python-grammar-digitpart"><code class="xref docutils literal notranslate"><span class="pre">digitpart</span></code></a> <span class="sx">&quot;.&quot;</span> [<a class="reference internal" href="#grammar-token-python-grammar-digitpart"><code class="xref docutils literal notranslate"><span class="pre">digitpart</span></code></a>] [<a class="reference internal" href="#grammar-token-python-grammar-exponent"><code class="xref docutils literal notranslate"><span class="pre">exponent</span></code></a>]
   | <span class="sx">&quot;.&quot;</span> <a class="reference internal" href="#grammar-token-python-grammar-digitpart"><code class="xref docutils literal notranslate"><span class="pre">digitpart</span></code></a> [<a class="reference internal" href="#grammar-token-python-grammar-exponent"><code class="xref docutils literal notranslate"><span class="pre">exponent</span></code></a>]
   | <a class="reference internal" href="#grammar-token-python-grammar-digitpart"><code class="xref docutils literal notranslate"><span class="pre">digitpart</span></code></a> <a class="reference internal" href="#grammar-token-python-grammar-exponent"><code class="xref docutils literal notranslate"><span class="pre">exponent</span></code></a>
<strong id="grammar-token-python-grammar-digitpart">digitpart</strong>: <a class="reference internal" href="#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a> ([<span class="sx">&quot;_&quot;</span>] <a class="reference internal" href="#grammar-token-python-grammar-digit"><code class="xref docutils literal notranslate"><span class="pre">digit</span></code></a>)*
<strong id="grammar-token-python-grammar-exponent">exponent</strong>:  (<span class="sx">&quot;e&quot;</span> | <span class="sx">&quot;E&quot;</span>) [<span class="sx">&quot;+&quot;</span> | <span class="sx">&quot;-&quot;</span>] <a class="reference internal" href="#grammar-token-python-grammar-digitpart"><code class="xref docutils literal notranslate"><span class="pre">digitpart</span></code></a>
</pre>
<div class="versionchanged">
<p><span class="versionmodified changed">Changed in version 3.6: </span>Underscores are now allowed for grouping purposes in literals.</p>
</div>
</section>
<section id="imaginary-literals">
<span id="imaginary"></span><span id="index-30"></span><h3><span class="section-number">2.6.3. </span>Imaginary literals<a class="headerlink" href="#imaginary-literals" title="Link to this heading">¶</a></h3>
<p>Python has <a class="reference internal" href="../library/stdtypes.html#typesnumeric"><span class="std std-ref">complex number</span></a> objects, but no complex
literals.
Instead, <em>imaginary literals</em> denote complex numbers with a zero
real part.</p>
<p>For example, in math, the complex number 3+4.2<em>i</em> is written
as the real number 3 added to the imaginary number 4.2<em>i</em>.
Python uses a similar syntax, except the imaginary unit is written as <code class="docutils literal notranslate"><span class="pre">j</span></code>
rather than <em>i</em>:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mi">3</span><span class="o">+</span><span class="mf">4.2</span><span class="n">j</span>
</pre></div>
</div>
<p>This is an expression composed
of the <a class="reference internal" href="#integers"><span class="std std-ref">integer literal</span></a> <code class="docutils literal notranslate"><span class="pre">3</span></code>,
the <a class="reference internal" href="#operators"><span class="std std-ref">operator</span></a> ‘<code class="docutils literal notranslate"><span class="pre">+</span></code>’,
and the <a class="reference internal" href="#imaginary"><span class="std std-ref">imaginary literal</span></a> <code class="docutils literal notranslate"><span class="pre">4.2j</span></code>.
Since these are three separate tokens, whitespace is allowed between them:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mi">3</span> <span class="o">+</span> <span class="mf">4.2</span><span class="n">j</span>
</pre></div>
</div>
<p>No whitespace is allowed <em>within</em> each token.
In particular, the <code class="docutils literal notranslate"><span class="pre">j</span></code> suffix, may not be separated from the number
before it.</p>
<p>The number before the <code class="docutils literal notranslate"><span class="pre">j</span></code> has the same syntax as a floating-point literal.
Thus, the following are valid imaginary literals:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mf">4.2</span><span class="n">j</span>
<span class="mf">3.14</span><span class="n">j</span>
<span class="mf">10.</span><span class="n">j</span>
<span class="mf">.001</span><span class="n">j</span>
<span class="mf">1e100j</span>
<span class="mf">3.14e-10</span><span class="n">j</span>
<span class="mf">3.14_15_93</span><span class="n">j</span>
</pre></div>
</div>
<p>Unlike in a floating-point literal the decimal point can be omitted if the
imaginary number only has an integer part.
The number is still evaluated as a floating-point number, not an integer:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mi">10</span><span class="n">j</span>
<span class="mi">0</span><span class="n">j</span>
<span class="mi">1000000000000000000000000</span><span class="n">j</span>   <span class="c1"># equivalent to 1e+24j</span>
</pre></div>
</div>
<p>The <code class="docutils literal notranslate"><span class="pre">j</span></code> suffix is case-insensitive.
That means you can use <code class="docutils literal notranslate"><span class="pre">J</span></code> instead:</p>
<div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="mf">3.14</span><span class="n">J</span>   <span class="c1"># equivalent to 3.14j</span>
</pre></div>
</div>
<p>Formally, imaginary literals are described by the following lexical definition:</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-imagnumber">imagnumber</strong>: (<a class="reference internal" href="#grammar-token-python-grammar-floatnumber"><code class="xref docutils literal notranslate"><span class="pre">floatnumber</span></code></a> | <a class="reference internal" href="#grammar-token-python-grammar-digitpart"><code class="xref docutils literal notranslate"><span class="pre">digitpart</span></code></a>) (<span class="sx">&quot;j&quot;</span> | <span class="sx">&quot;J&quot;</span>)
</pre>
</section>
</section>
<section id="operators-and-delimiters">
<span id="lexical-ellipsis"></span><span id="operators"></span><span id="delimiters"></span><h2><span class="section-number">2.7. </span>Operators and delimiters<a class="headerlink" href="#operators-and-delimiters" title="Link to this heading">¶</a></h2>
<p id="index-31">The following grammar defines <em class="dfn">operator</em> and <em class="dfn">delimiter</em> tokens,
that is, the generic <a class="reference internal" href="../library/token.html#token.OP" title="token.OP"><code class="xref py py-data docutils literal notranslate"><span class="pre">OP</span></code></a> token type.
A <a class="reference internal" href="../library/token.html#token-operators-delimiters"><span class="std std-ref">list of these tokens and their names</span></a>
is also available in the <code class="xref py py-mod docutils literal notranslate"><span class="pre">token</span></code> module documentation.</p>
<pre class="highlight">
<strong id="grammar-token-python-grammar-OP">OP</strong>:
   | assignment_operator
   | bitwise_operator
   | comparison_operator
   | enclosing_delimiter
   | other_delimiter
   | arithmetic_operator
   | <span class="sx">&quot;...&quot;</span>
   | other_op

<strong id="grammar-token-python-grammar-assignment_operator">assignment_operator</strong>:   <span class="sx">&quot;+=&quot;</span> | <span class="sx">&quot;-=&quot;</span> | <span class="sx">&quot;*=&quot;</span> | <span class="sx">&quot;**=&quot;</span> | <span class="sx">&quot;/=&quot;</span>  | <span class="sx">&quot;//=&quot;</span> | <span class="sx">&quot;%=&quot;</span> |
                       <span class="sx">&quot;&amp;=&quot;</span> | <span class="sx">&quot;|=&quot;</span> | <span class="sx">&quot;^=&quot;</span> | <span class="sx">&quot;&lt;&lt;=&quot;</span> | <span class="sx">&quot;&gt;&gt;=&quot;</span> | <span class="sx">&quot;&#64;=&quot;</span>  | <span class="sx">&quot;:=&quot;</span>
<strong id="grammar-token-python-grammar-bitwise_operator">bitwise_operator</strong>:      <span class="sx">&quot;&amp;&quot;</span>  | <span class="sx">&quot;|&quot;</span>  | <span class="sx">&quot;^&quot;</span>  | <span class="sx">&quot;~&quot;</span>   | <span class="sx">&quot;&lt;&lt;&quot;</span>  | <span class="sx">&quot;&gt;&gt;&quot;</span>
<strong id="grammar-token-python-grammar-comparison_operator">comparison_operator</strong>:   <span class="sx">&quot;&lt;=&quot;</span> | <span class="sx">&quot;&gt;=&quot;</span> | <span class="sx">&quot;&lt;&quot;</span>  | <span class="sx">&quot;&gt;&quot;</span>   | <span class="sx">&quot;==&quot;</span>  | <span class="sx">&quot;!=&quot;</span>
<strong id="grammar-token-python-grammar-enclosing_delimiter">enclosing_delimiter</strong>:   <span class="sx">&quot;(&quot;</span>  | <span class="sx">&quot;)&quot;</span>  | <span class="sx">&quot;[&quot;</span>  | <span class="sx">&quot;]&quot;</span>   | <span class="sx">&quot;{&quot;</span>   | <span class="sx">&quot;}&quot;</span>
<strong id="grammar-token-python-grammar-other_delimiter">other_delimiter</strong>:       <span class="sx">&quot;,&quot;</span>  | <span class="sx">&quot;:&quot;</span>  | <span class="sx">&quot;!&quot;</span>  | <span class="sx">&quot;;&quot;</span>   | <span class="sx">&quot;=&quot;</span>   | <span class="sx">&quot;-&gt;&quot;</span>
<strong id="grammar-token-python-grammar-arithmetic_operator">arithmetic_operator</strong>:   <span class="sx">&quot;+&quot;</span>  | <span class="sx">&quot;-&quot;</span>  | <span class="sx">&quot;**&quot;</span> | <span class="sx">&quot;*&quot;</span>   | <span class="sx">&quot;//&quot;</span>  | <span class="sx">&quot;/&quot;</span>   | <span class="sx">&quot;%&quot;</span>
<strong id="grammar-token-python-grammar-other_op">other_op</strong>:              <span class="sx">&quot;.&quot;</span>  | <span class="sx">&quot;&#64;&quot;</span>
</pre>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>Generally, <em>operators</em> are used to combine <a class="reference internal" href="expressions.html#expressions"><span class="std std-ref">expressions</span></a>,
while <em>delimiters</em> serve other purposes.
However, there is no clear, formal distinction between the two categories.</p>
<p>Some tokens can serve as either operators or delimiters, depending on usage.
For example, <code class="docutils literal notranslate"><span class="pre">*</span></code> is both the multiplication operator and a delimiter used
for sequence unpacking, and <code class="docutils literal notranslate"><span class="pre">&#64;</span></code> is both the matrix multiplication and
a delimiter that introduces decorators.</p>
<p>For some tokens, the distinction is unclear.
For example, some people consider <code class="docutils literal notranslate"><span class="pre">.</span></code>, <code class="docutils literal notranslate"><span class="pre">(</span></code>, and <code class="docutils literal notranslate"><span class="pre">)</span></code> to be delimiters, while others
see the <a class="reference internal" href="../library/functions.html#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate"><span class="pre">getattr()</span></code></a> operator and the function call operator(s).</p>
<p>Some of Python’s operators, like <code class="docutils literal notranslate"><span class="pre">and</span></code>, <code class="docutils literal notranslate"><span class="pre">or</span></code>, and <code class="docutils literal notranslate"><span class="pre">not</span> <span class="pre">in</span></code>, use
<a class="reference internal" href="#keywords"><span class="std std-ref">keyword</span></a> tokens rather than “symbols” (operator tokens).</p>
</div>
<p>A sequence of three consecutive periods (<code class="docutils literal notranslate"><span class="pre">...</span></code>) has a special
meaning as an <a class="reference internal" href="../library/constants.html#Ellipsis" title="Ellipsis"><code class="xref py py-data docutils literal notranslate"><span class="pre">Ellipsis</span></code></a> literal.</p>
</section>
</section>


            <div class="clearer"></div>
          </div>
        </div>
      </div>
      <div class="sphinxsidebar" role="navigation" aria-label="Main">
        <div class="sphinxsidebarwrapper">
  <div>
    <h3><a href="../contents.html">Table of Contents</a></h3>
    <ul>
<li><a class="reference internal" href="#">2. Lexical analysis</a><ul>
<li><a class="reference internal" href="#line-structure">2.1. Line structure</a><ul>
<li><a class="reference internal" href="#logical-lines">2.1.1. Logical lines</a></li>
<li><a class="reference internal" href="#physical-lines">2.1.2. Physical lines</a></li>
<li><a class="reference internal" href="#comments">2.1.3. Comments</a></li>
<li><a class="reference internal" href="#encoding-declarations">2.1.4. Encoding declarations</a></li>
<li><a class="reference internal" href="#explicit-line-joining">2.1.5. Explicit line joining</a></li>
<li><a class="reference internal" href="#implicit-line-joining">2.1.6. Implicit line joining</a></li>
<li><a class="reference internal" href="#blank-lines">2.1.7. Blank lines</a></li>
<li><a class="reference internal" href="#indentation">2.1.8. Indentation</a></li>
<li><a class="reference internal" href="#whitespace-between-tokens">2.1.9. Whitespace between tokens</a></li>
<li><a class="reference internal" href="#end-marker">2.1.10. End marker</a></li>
</ul>
</li>
<li><a class="reference internal" href="#other-tokens">2.2. Other tokens</a></li>
<li><a class="reference internal" href="#names-identifiers-and-keywords">2.3. Names (identifiers and keywords)</a><ul>
<li><a class="reference internal" href="#keywords">2.3.1. Keywords</a></li>
<li><a class="reference internal" href="#soft-keywords">2.3.2. Soft Keywords</a></li>
<li><a class="reference internal" href="#reserved-classes-of-identifiers">2.3.3. Reserved classes of identifiers</a></li>
<li><a class="reference internal" href="#non-ascii-characters-in-names">2.3.4. Non-ASCII characters in names</a></li>
</ul>
</li>
<li><a class="reference internal" href="#literals">2.4. Literals</a></li>
<li><a class="reference internal" href="#string-and-bytes-literals">2.5. String and Bytes literals</a><ul>
<li><a class="reference internal" href="#triple-quoted-strings">2.5.1. Triple-quoted strings</a></li>
<li><a class="reference internal" href="#string-prefixes">2.5.2. String prefixes</a></li>
<li><a class="reference internal" href="#formal-grammar">2.5.3. Formal grammar</a></li>
<li><a class="reference internal" href="#escape-sequences">2.5.4. Escape sequences</a><ul>
<li><a class="reference internal" href="#ignored-end-of-line">2.5.4.1. Ignored end of line</a></li>
<li><a class="reference internal" href="#escaped-characters">2.5.4.2. Escaped characters</a></li>
<li><a class="reference internal" href="#octal-character">2.5.4.3. Octal character</a></li>
<li><a class="reference internal" href="#hexadecimal-character">2.5.4.4. Hexadecimal character</a></li>
<li><a class="reference internal" href="#named-unicode-character">2.5.4.5. Named Unicode character</a></li>
<li><a class="reference internal" href="#hexadecimal-unicode-characters">2.5.4.6. Hexadecimal Unicode characters</a></li>
<li><a class="reference internal" href="#unrecognized-escape-sequences">2.5.4.7. Unrecognized escape sequences</a></li>
</ul>
</li>
<li><a class="reference internal" href="#bytes-literals">2.5.5. Bytes literals</a></li>
<li><a class="reference internal" href="#raw-string-literals">2.5.6. Raw string literals</a></li>
<li><a class="reference internal" href="#formatted-string-literals">2.5.7. f-strings</a></li>
<li><a class="reference internal" href="#template-string-literals">2.5.8. t-strings</a></li>
<li><a class="reference internal" href="#formal-grammar-for-f-strings">2.5.9. Formal grammar for f-strings</a></li>
</ul>
</li>
<li><a class="reference internal" href="#numeric-literals">2.6. Numeric literals</a><ul>
<li><a class="reference internal" href="#integer-literals">2.6.1. Integer literals</a></li>
<li><a class="reference internal" href="#floating-point-literals">2.6.2. Floating-point literals</a></li>
<li><a class="reference internal" href="#imaginary-literals">2.6.3. Imaginary literals</a></li>
</ul>
</li>
<li><a class="reference internal" href="#operators-and-delimiters">2.7. Operators and delimiters</a></li>
</ul>
</li>
</ul>

  </div>
  <div>
    <h4>Previous topic</h4>
    <p class="topless"><a href="introduction.html"
                          title="previous chapter"><span class="section-number">1. </span>Introduction</a></p>
  </div>
  <div>
    <h4>Next topic</h4>
    <p class="topless"><a href="datamodel.html"
                          title="next chapter"><span class="section-number">3. </span>Data model</a></p>
  </div>
  <script>
    document.addEventListener('DOMContentLoaded', () => {
        const title = document.querySelector('meta[property="og:title"]').content;
        const elements = document.querySelectorAll('.improvepage');
        const pageurl = window.location.href.split('?')[0];
        elements.forEach(element => {
            const url = new URL(element.href.split('?')[0].replace("-nojs", ""));
            url.searchParams.set('pagetitle', title);
            url.searchParams.set('pageurl', pageurl);
            url.searchParams.set('pagesource', "reference/lexical_analysis.rst");
            element.href = url.toString();
        });
    });
  </script>
  <div role="note" aria-label="source link">
    <h3>This page</h3>
    <ul class="this-page-menu">
      <li><a href="../bugs.html">Report a bug</a></li>
      <li><a class="improvepage" href="../improve-page-nojs.html">Improve this page</a></li>
      <li>
        <a href="https://github.com/python/cpython/blob/main/Doc/reference/lexical_analysis.rst?plain=1"
            rel="nofollow">Show source
        </a>
      </li>
      
    </ul>
  </div>
        </div>
<div id="sidebarbutton" title="Collapse sidebar">
<span>«</span>
</div>

      </div>
      <div class="clearer"></div>
    </div>  
    <div class="related" role="navigation" aria-label="Related">
      <h3>Navigation</h3>
      <ul>
        <li class="right" style="margin-right: 10px">
          <a href="../genindex.html" title="General Index"
             >index</a></li>
        <li class="right" >
          <a href="../py-modindex.html" title="Python Module Index"
             >modules</a> |</li>
        <li class="right" >
          <a href="datamodel.html" title="3. Data model"
             >next</a> |</li>
        <li class="right" >
          <a href="introduction.html" title="1. Introduction"
             >previous</a> |</li>

          <li><img src="../_static/py.svg" alt="Python logo" style="vertical-align: middle; margin-top: -1px"></li>
          <li><a href="https://www.python.org/">Python</a> &#187;</li>
          <li class="switchers">
            <div class="language_switcher_placeholder"></div>
            <div class="version_switcher_placeholder"></div>
          </li>
          <li>
              
          </li>
    <li id="cpython-language-and-version">
      <a href="../index.html">3.14.4 Documentation</a> &#187;
    </li>

          <li class="nav-item nav-item-1"><a href="index.html" >The Python Language Reference</a> &#187;</li>
        <li class="nav-item nav-item-this"><a href=""><span class="section-number">2. </span>Lexical analysis</a></li>
                <li class="right">
                    

    <div class="inline-search" role="search">
        <form class="inline-search" action="../search.html" method="get">
          <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" id="search-box">
          <input type="submit" value="Go">
        </form>
    </div>
                     |
                </li>
            <li class="right">
<label class="theme-selector-label">
    Theme
    <select class="theme-selector" oninput="activateTheme(this.value)">
        <option value="auto" selected>Auto</option>
        <option value="light">Light</option>
        <option value="dark">Dark</option>
    </select>
</label> |</li>
            
      </ul>
    </div>  
    <div class="footer">
    &copy; <a href="../copyright.html">Copyright</a> 2001 Python Software Foundation.
    <br>
    This page is licensed under the Python Software Foundation License Version 2.
    <br>
    Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
    <br>
    
      See <a href="/license.html">History and License</a> for more information.<br>
    
    
    <br>

    The Python Software Foundation is a non-profit corporation.
<a href="https://www.python.org/psf/donations/">Please donate.</a>
<br>
    <br>
      Last updated on Apr 07, 2026 (13:52 UTC).
    
      <a href="/bugs.html">Found a bug</a>?
    
    <br>

    Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 8.2.3.
    </div>

  </body>
</html>