bidict/docs/other-functionality.rst

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Other Functionality
===================
:func:`bidict.inverted`
-----------------------
bidict provides the :class:`~bidict.inverted` iterator
to help you get inverse items from various types of objects.
Pass in a mapping to get the inverse mapping:
.. doctest::
>>> from bidict import inverted
>>> it = inverted({1: 'one'})
>>> {k: v for (k, v) in it}
{'one': 1}
...an iterable of pairs to get the pairs' inverses:
.. doctest::
>>> list(inverted([(1, 'one'), (2, 'two')]))
[('one', 1), ('two', 2)]
>>> list(inverted((i*i, i) for i in range(2, 5)))
[(2, 4), (3, 9), (4, 16)]
...or any object implementing an ``__inverted__`` method,
which objects that already know their own inverses (such as bidicts)
can implement themselves:
.. testsetup::
from bidict import bidict, OrderedBidict
.. doctest::
>>> dict(inverted(bidict({1: 'one'})))
{'one': 1}
>>> list(inverted(OrderedBidict([(2, 4), (3, 9)])))
[(4, 2), (9, 3)]