permutation

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GitHub <https://github.com/jwodder/permutation>_ | PyPI <https://pypi.org/project/permutation>_ | Documentation <https://permutation.readthedocs.io>_ | Issues <https://github.com/jwodder/permutation/issues>_ | Changelog <https://github.com/jwodder/permutation/blob/master/CHANGELOG.md>_

permutation provides a Permutation class for representing permutations <https://en.wikipedia.org/wiki/Permutation>_ of finitely many positive integers in Python. Supported operations & properties include inverses, (group theoretic) order, parity, composition/multiplication, cycle decomposition, cycle notation, word representation, Lehmer codes, and, of course, use as a callable on integers.

Installation

permutation requires Python 3.8 or higher. Just use pip <https://pip.pypa.io>_ for Python 3 (You have pip, right?) to install::

python3 -m pip install permutation

Examples

from permutation import Permutation p = Permutation(2, 1, 4, 5, 3) p(1) 2 p(3) 4 p(42) 42 p.to_cycles() [(1, 2), (3, 4, 5)] print(p) (1 2)(3 4 5) print(p.inverse()) (1 2)(3 5 4) p.degree 5 p.order 6 p.is_even False p.lehmer(5) 27 q = Permutation.cycle(1,2,3) print(p * q) (2 4 5 3) print(q * p) (1 3 4 5) for p in Permutation.group(3): ... print(p) ... 1 (1 2) (2 3) (1 3 2) (1 2 3) (1 3)