Python uses the Bi- Al dictionary structure of the bidict Module

Python uses the Bi- Al dictionary structure of the bidict Module

Quick Start

The module provides three classes to handle one-to-one ing operations.
'Idict ', 'inverted', 'namedidict'

>>> import bidict>>> dir(bidict)['MutableMapping', '_LEGALNAMEPAT', '_LEGALNAMERE', '__builtins__', '__doc__', '__file__', '__name__', '__package__', 'bidict', 'inverted', 'namedbidict', 're', 'wraps'] 

1. bidict class:

>>> From bidict import bidict >>> D = bidict ({'A': 'B'}) >>> D ['a'] 'B'> D [: 'B'] 'A'> ~ D # reverse dictionary bidict ({'B': 'A'}) >>> dict (D) # convert to normal dictionary {'A ': 'B' }>>> D ['C'] = 'C' # to add elements. You can use the> Dbidict ({'A ': 'B', 'C': 'C '})

2. inverted class, which reverses the dictionary key value

>>> seq = [(1, 'one'), (2, 'two'), (3, 'three')]>>> list(inverted(seq))    [('one', 1), ('two', 2), ('three', 3)]

3. namedbidict (mapname, fwdname, invname ):

>>> CoupleMap = namedbidict('CoupleMap', 'husbands', 'wives')>>> famous = CoupleMap({'bill': 'hillary'})>>> famous.husbands['bill']'hillary'>>> famous.wives['hillary']'bill'>>> famous.husbands['barack'] = 'michelle'>>> del famous.wives['hillary']>>> famousCoupleMap({'barack': 'michelle'})

More

If you do not like the colon method, you can use the namedbidict class to give two aliases to the bidirectional dictionary. In this way, two subdictionaries, forward and reverse, are provided. In fact, it still exists in the form of a bidirectional dictionary:

>>> HTMLEntities = namedbidict('HTMLEntities', 'names', 'codepoints')>>> entities = HTMLEntities({'lt': 60, 'gt': 62, 'amp': 38}) # etc>>> entities.names['lt']60>>> entities.codepoints[38]'amp'

You can also use the unary inverse operator "~ "Obtain the bidict inverse ing dictionary.

>>> import bidict>>> from bidict import bidict>>> husbands2wives = bidict({'john': 'jackie'})>>> ~husbands2wivesbidict({'jackie': 'john'})

Note the following when adding brackets because ~ The priority is lower than the brackets:

>>> import bidict>>> from bidict import bidict>>> husbands2wives = bidict({'john': 'jackie'})>>> ~husbands2wivesbidict({'jackie': 'john'})

Note the following when adding brackets because ~ The priority is lower than the brackets:

>>> (~bi)['one']1

Bidict is not a subclass of dict, but its API is the superset of dict (without the fromkeys method, instead of the MutableMapping interface ).

Inverted of the iterator class will flip the key and value, for example:

>>> seq = [(1, 'one'), (2, 'two'), (3, 'three')]>>> list(inverted(seq))[('one', 1), ('two', 2), ('three', 3)]

The invert () method of bidict is similar to that of inverted. Dependency module: MutableMapping in collections, wraps and re in functools.

Bidict can be compared with the dictionary

>>> bi == bidict({1:'one'})>>> bi == dict([(1, 'one')])True

Other commonly used dictionary methods, bidict also supports:

>>> bi.get('one')1>>> bi.setdefault('one', 2)1>>> bi.setdefault('two', 2)2>>> len(bi) # calls __len__2>>> bi.pop('one')1>>> bi.popitem()('two', 2)>>> bi.inv.setdefault(3, 'three')'three'>>> bibidict({'three': 3})>>> [key for key in bi] # calls __iter__, returns keys like dict['three']>>> 'three' in bi # calls __contains__True>>> list(bi.keys())['three']>>> list(bi.values())[3]>>> bi.update([('four', 4)])>>> bi.update({'five': 5}, six=6, seven=7)>>> sorted(bi.items(), key=lambda x: x[1])[('three', 3), ('four', 4), ('five', 5), ('six', 6), ('seven', 7)]