frozenlist

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Introduction

frozenlist.FrozenList is a list-like structure which implements collections.abc.MutableSequence. The list is mutable until FrozenList.freeze is called, after which list modifications raise RuntimeError:

from frozenlist import FrozenList fl = FrozenList([17, 42]) fl.append('spam') fl.append('Vikings') fl <FrozenList(frozen=False, [17, 42, 'spam', 'Vikings'])> fl.freeze() fl <FrozenList(frozen=True, [17, 42, 'spam', 'Vikings'])> fl.frozen True fl.append("Monty") Traceback (most recent call last): File "", line 1, in File "frozenlist/_frozenlist.pyx", line 97, in frozenlist._frozenlist.FrozenList.append self._check_frozen() File "frozenlist/_frozenlist.pyx", line 19, in frozenlist._frozenlist.FrozenList._check_frozen raise RuntimeError("Cannot modify frozen list.") RuntimeError: Cannot modify frozen list.

FrozenList is also hashable, but only when frozen. Otherwise it also throws a RuntimeError:

fl = FrozenList([17, 42, 'spam']) hash(fl) Traceback (most recent call last): File "", line 1, in File "frozenlist/_frozenlist.pyx", line 111, in frozenlist._frozenlist.FrozenList.hash raise RuntimeError("Cannot hash unfrozen list.") RuntimeError: Cannot hash unfrozen list. fl.freeze() hash(fl) 3713081631934410656 dictionary = {fl: 'Vikings'} # frozen fl can be a dict key dictionary {<FrozenList(frozen=True, [1, 2])>: 'Vikings'}

Installation

::

$ pip install frozenlist

The library requires Python 3.8 or newer.

Documentation

https://frozenlist.aio-libs.org

Communication channels

We have a Matrix Space #aio-libs-space:matrix.org <https://matrix.to/#/%23aio-libs-space:matrix.org>_ which is also accessible via Gitter.

Requirements

• Python >= 3.8

License

frozenlist is offered under the Apache 2 license.

Source code

The project is hosted on GitHub_

Please file an issue in the bug tracker <https://github.com/aio-libs/frozenlist/issues>_ if you have found a bug or have some suggestions to improve the library.

.. _GitHub: https://github.com/aio-libs/frozenlist