docs/source/tree.rst - main - githubmirror/rich

docs/source/tree.rst
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Will McGugan
doc
09 янв 2021, 22:37
09 янв 2021, 22:37400671d
Tree
====

Rich has a :class:`~rich.tree.Tree` class which can generate a tree view in the terminal. A tree view is a great way of presenting the contents of a filesystem or any other hierarchical data. Each branch of the tree can have a label which may be text or any other Rich renderable.

Run the following command to see a demonstration of a Rich tree::

    python -m rich.tree

The following code creates and prints a tree with a simple text label::

    from rich.tree import Tree
    from rich import print

    tree = Tree("Rich Tree")
    print(tree)

With only a single ``Tree`` instance this will output nothing more than the text "Rich Tree". Things get more interesting when we call :meth:`~rich.tree.Tree.add` to add more branches to the Tree. The following code adds two more branches::

    tree.add("foo")
    tree.add("bar")
    print(tree)

The tree will now have two branches connected to the original tree with guide lines.

When you call :meth:`~rich.tree.Tree.add` a new Tree instance is returned. You can use this instance to add more branches to, and build up a more complex tree. Let's add a few more levels to the tree::

    baz_tree = tree.add("baz")
    baz_tree.add("[red]Red").add("[green]Green").add("[blue]Blue")
    print(tree)


Tree Styles
~~~~~~~~~~~

The Tree constructor and :meth:`~rich.tree.Tree.add` method allows you to specify a ``style`` argument which sets a style for the entire branch, and ``guide_style`` which sets the style for the guide lines. These styles are inherited by the branches and will apply to any sub-trees as well.

If you set ``guide_style`` to bold, Rich will select the thicker variations of unicode line characters. Similarly, if you select the "underline2" style you will get double line style of unicode characters.


Examples
~~~~~~~~

For a more practical demonstration, see `tree.py <https://github.com/willmcgugan/rich/blob/master/examples/tree.py>`_ which can generate a tree view of a directory in your hard drive.