Python for Education: Permutations

Andrzej Kapanowski

Abstract


Python implementation of permutations is presented. Two classes are introduced: Perm for permutations and Group for permutation groups. The class Perm is based on Python dictionaries and utilize cycle notation. The methods of calculation for the perm order, parity, ranking and unranking are given. A random permutation generation is also shown. The class Group is very simple and it is also based on dictionaries. It is mainly the presentation of the permutation groups interface with methods for the group order, subgroups (normalizer, centralizer, center, stabilizer), orbits, and several tests. The corresponding Python code is contained in the modules perms and groups.

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