permutations 0.2.0
Python library for instantiating and working with permutation collections that provide efficient implementations of all sequence methods (including random-access retrieval by index).
License: MIT
Requires Python: >=3.7

============
permutations
============

Python library for instantiating and working with permutation collections that provide efficient implementations of all sequence methods (including random-access retrieval by index).

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Purpose
-------

.. |itertools_permutations| replace:: ``itertools.permutations``
.. _itertools_permutations: https://docs.python.org/3/library/itertools.html#itertools.permutations

.. |Sequence| replace:: ``Sequence``
.. _Sequence: https://docs.python.org/3/library/collections.abc.html#collections.abc.Sequence

This library provides a drop-in alternative to the built-in |itertools_permutations|_ function. This alternative implements the features of a |Sequence|_, including the ability to access individual entries using their index (without iterating over all permutations up to that point).

Installation and Usage
----------------------
This library is available as a `package on PyPI <https://pypi.org/project/permutations>`__:

.. code-block:: bash

    python -m pip install permutations

The library can be imported in the usual ways:
                              
.. code-block:: python

    import permutations
    from permutations import permutations

Examples
^^^^^^^^

.. |permutations| replace:: ``permutations``
.. _permutations: https://permutations.readthedocs.io/en/0.2.0/_source/permutations.html#permutations.permutations.permutations

.. |Iterable| replace:: ``Iterable``
.. _Iterable: https://docs.python.org/3/library/collections.abc.html#collections.abc.Iterable

The |permutations|_ class can be used in the same way as the built-in |itertools_permutations|_ function:

.. code-block:: python

    >>> list(permutations(range(3)))
    [(0, 1, 2), (0, 2, 1), (1, 0, 2), (1, 2, 0), (2, 0, 1), (2, 1, 0)]
    >>> list(permutations(range(3), 2))
    [(0, 1), (0, 2), (1, 0), (1, 2), (2, 0), (2, 1)]

However, in addition to acting as an |Iterable|_ containing a collection of permutations, an instance of |permutations|_ also acts as a |Sequence|_. In particular, it supports retrieval of specific permutations by their index and its length can be determined without iterating over its elements:

.. code-block:: python

    >>> ps = permutations(range(5))
    >>> ps[37]
    (1, 3, 0, 4, 2)
    >>> permutations(range(20))[7**20]
    (0, 13, 9, 6, 14, 8, 17, 1, 5, 12, 15, 18, 11, 16, 10, 2, 3, 4, 19, 7)
    >>> len(permutations(range(8))) == 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
    True

Development
-----------
All installation and development dependencies are fully specified in ``pyproject.toml``. The ``project.optional-dependencies`` object is used to `specify optional requirements <https://peps.python.org/pep-0621>`__ for various development tasks. This makes it possible to specify additional options (such as ``docs``, ``lint``, and so on) when performing installation using `pip <https://pypi.org/project/pip>`__:

.. code-block:: bash

    python -m pip install .[docs,lint]

Documentation
^^^^^^^^^^^^^
The documentation can be generated automatically from the source files using `Sphinx <https://www.sphinx-doc.org>`__:

.. code-block:: bash

    python -m pip install .[docs]
    cd docs
    sphinx-apidoc -f -E --templatedir=_templates -o _source .. && make html

Testing and Conventions
^^^^^^^^^^^^^^^^^^^^^^^
All unit tests are executed and their coverage is measured when using `pytest <https://docs.pytest.org>`__ (see the ``pyproject.toml`` file for configuration details):

.. code-block:: bash

    python -m pip install .[test]
    python -m pytest

Alternatively, all unit tests are included in the module itself and can be executed using `doctest <https://docs.python.org/3/library/doctest.html>`__:

.. code-block:: bash

    python src/permutations/permutations.py -v

Style conventions are enforced using `Pylint <https://pylint.readthedocs.io>`__:

.. code-block:: bash

    python -m pip install .[lint]
    python -m pylint src/permutations

Contributions
^^^^^^^^^^^^^
In order to contribute to the source code, open an issue or submit a pull request on the `GitHub page <https://github.com/lapets/permutations>`__ for this library.

Versioning
^^^^^^^^^^
The version number format for this library and the changes to the library associated with version number increments conform with `Semantic Versioning 2.0.0 <https://semver.org/#semantic-versioning-200>`__.

Publishing
^^^^^^^^^^
This library can be published as a `package on PyPI <https://pypi.org/project/permutations>`__ by a package maintainer. First, install the dependencies required for packaging and publishing:

.. code-block:: bash

    python -m pip install .[publish]

Ensure that the correct version number appears in ``pyproject.toml``, and that any links in this README document to the Read the Docs documentation of this package (or its dependencies) have appropriate version numbers. Also ensure that the Read the Docs project for this library has an `automation rule <https://docs.readthedocs.io/en/stable/automation-rules.html>`__ that activates and sets as the default all tagged versions. Create and push a tag for this version (replacing ``?.?.?`` with the version number):

.. code-block:: bash

    git tag ?.?.?
    git push origin ?.?.?

Remove any old build/distribution files. Then, package the source into a distribution archive:

.. code-block:: bash

    rm -rf build dist src/*.egg-info
    python -m build --sdist --wheel .

Finally, upload the package distribution archive to `PyPI <https://pypi.org>`__:

.. code-block:: bash

    python -m twine upload dist/*