bijection

Bijections are functions that map keys to unique values, ie. one-to-one, onto functions. See: https://en.wikipedia.org/wiki/Bijection

bijection maintains the inverse mapping on bijection.inverse which is itself an instance of bijection.

Examples

>>> from collections_extended import bijection
>>> bij = bijection({'a': 1, 'b': 2, 'c': 3})
>>> bij.inverse[2]
'b'
>>> bij['a'] = 2
>>> bij == bijection({'a': 2, 'c': 3})
True
>>> bij.inverse[1] = 'a'
>>> bij == bijection({'a': 1, 'c': 3})
True
>>> bij.inverse.inverse is bij
True

API

class collections_extended.bijection(iterable=None, **kwarg)

Bases: collections.abc.MutableMapping

A one-to-one onto mapping, a dict with unique values.

__init__(iterable=None, **kwarg)

Create a bijection from an iterable.

Matches dict.__init__.

property inverse

Return the inverse of this bijection.

clear()

Remove everything from this bijection.

copy()

Return a copy of this bijection.

items()

See Mapping.items.

keys()

See Mapping.keys.

values()

See Mapping.values.