https://github.com/wheerd/multiset

A multiset implementation for python
https://github.com/wheerd/multiset

data-structure library multiset python

Last synced: 4 days ago
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A multiset implementation for python

• Host: GitHub
• URL: https://github.com/wheerd/multiset
• Owner: wheerd
• License: mit
• Created: 2016-10-15T07:44:06.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2024-08-27T13:16:31.000Z (5 months ago)
• Last Synced: 2025-01-18T21:45:06.299Z (11 days ago)
• Topics: data-structure, library, multiset, python
• Language: Python
• Size: 132 KB
• Stars: 39
• Watchers: 2
• Forks: 10
• Open Issues: 8
• Metadata Files:
  • Readme: README.rst
  • License: LICENSE

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README

        
multiset

========

This package provides a multiset_ implementation for python.

|pypi| |coverage| |build| |docs|

Overview

--------

A multiset is similar to the builtin set_, but it allows an element to occur multiple times.

It is an unordered collection of elements which have to be hashable just like in a set_.

It supports the same methods and operations as set_ does, e.g. membership test, union, intersection, and

(symmetric) difference::

    >>> set1 = Multiset('aab')

    >>> set2 = Multiset('abc')

    >>> sorted(set1 | set2)

    ['a', 'a', 'b', 'c']

Multisets can be used in combination with sets_::

    >>> Multiset('aab') >= {'a', 'b'}

    True

Multisets are mutable::

    >>> set1.update('bc')

    >>> sorted(set1)

    ['a', 'a', 'b', 'b', 'c']

There is an immutable version similar to the frozenset_ which is also hashable::

    >>> set1 = FrozenMultiset('abc')

    >>> set2 = FrozenMultiset('abc')

    >>> hash(set1) == hash(set2)

    True

    >>> set1 is set2

    False

The implementation is based on a dict_ that maps the elements to their multiplicity in the multiset.

Hence, some dictionary operations are supported.

In contrast to the `collections.Counter`_ from the standard library, it has proper support for set

operations and only allows positive counts. Also, elements with a zero multiplicity are automatically

removed from the multiset.

Installation

------------

Installing `multiset` is simple with `pip `_::

    $ pip install multiset

Documentation

-------------

The documentation is available at `Read the Docs`_.

.. _`Read the Docs`: http://multiset.readthedocs.io/

API Documentation

.................

If you are looking for information on a particular method of the Multiset class, have a look at the

`API Documentation`_. It is automatically generated from the docstrings.

.. _`API Documentation`: http://multiset.readthedocs.io/en/latest/api.html

License

-------

Licensed under the MIT_ license.

.. _multiset: https://en.wikipedia.org/wiki/Multiset

.. _set: https://docs.python.org/3.10/library/stdtypes.html#set-types-set-frozenset

.. _sets: set_

.. _frozenset: set_

.. _dict: https://docs.python.org/3.10/library/stdtypes.html#mapping-types-dict

.. _`collections.Counter`: https://docs.python.org/3.10/library/collections.html#collections.Counter

.. _MIT: https://opensource.org/licenses/MIT

.. |pypi| image:: https://img.shields.io/pypi/v/multiset.svg?style=flat-square&label=latest%20stable%20version

    :target: https://pypi.python.org/pypi/multiset

    :alt: Latest version released on PyPi

.. |coverage| image:: https://coveralls.io/repos/github/wheerd/multiset/badge.svg?branch=master

    :target: https://coveralls.io/github/wheerd/multiset?branch=master

    :alt: Test coverage

.. |build| image:: https://github.com/wheerd/multiset/workflows/Tests/badge.svg?branch=master

    :target: https://github.com/wheerd/multiset/actions?query=workflow%3ATests

    :alt: Build status of the master branch

.. |docs| image:: https://readthedocs.org/projects/multiset/badge/?version=latest

    :target: http://multiset.readthedocs.io/en/latest/?badge=latest

    :alt: Documentation Status