mirror of https://github.com/jab/bidict.git
63 lines
1.5 KiB
ReStructuredText
63 lines
1.5 KiB
ReStructuredText
.. _basic-usage:
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Basic Usage
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-----------
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Let's return to the example from the :ref:`intro`::
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>>> from bidict import bidict
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>>> element_by_symbol = bidict(H='hydrogen')
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As we saw, this behaves just like a dict,
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but maintains a special
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:attr:`inv <bidict.BidirectionalMapping.inv>` attribute
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giving access to inverse mappings::
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>>> element_by_symbol.inv['helium'] = 'He'
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>>> del element_by_symbol.inv['hydrogen']
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>>> element_by_symbol
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bidict({'He': 'helium'})
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The rest of the
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:class:`collections.abc.MutableMapping` ABC
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is also supported::
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>>> 'C' in element_by_symbol
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False
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>>> element_by_symbol.get('C', 'carbon')
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'carbon'
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>>> element_by_symbol.pop('He')
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'helium'
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>>> element_by_symbol
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bidict({})
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>>> element_by_symbol.update(Hg='mercury')
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>>> element_by_symbol
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bidict({'Hg': 'mercury'})
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>>> 'mercury' in element_by_symbol.inv
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True
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>>> element_by_symbol.inv.pop('mercury')
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'Hg'
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Because inverse mappings are maintained alongside forward mappings,
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referencing a bidict's inverse
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is always a constant-time operation.
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.. include:: values-hashable.rst.inc
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.. include:: unique-values.rst.inc
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.. include:: loosebidict.rst.inc
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.. include:: beware-on_dup_kv-overwrite.rst.inc
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.. include:: order-matters.rst.inc
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.. include:: interop.rst.inc
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Hopefully bidict feels right at home
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among the Python built-ins you already know.
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Proceed to :ref:`other-bidict-types`
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for documentation on the remaining bidict flavors.
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