class MultiKeyDict(object):
def __init__(self, **kwargs):
self._keys = {}
self._data = {}
for k, v in kwargs.iteritems():
self[k] = v
def __getitem__(self, key):
try:
return self._data[key]
except KeyError:
return self._data[self._keys[key]]
def __setitem__(self, key, val):
try:
self._data[self._keys[key]] = val
except KeyError:
if isinstance(key, tuple):
if not key:
raise ValueError(u'Empty tuple cannot be used as a key')
key, other_keys = key[0], key[1:]
else:
other_keys = []
self._data[key] = val
for k in other_keys:
self._keys[k] = key
def add_keys(self, to_key, new_keys):
if to_key not in self._data:
to_key = self._keys[to_key]
for key in new_keys:
self._keys[key] = to_key
@classmethod
def from_dict(cls, dic):
result = cls()
for key, val in dic.items():
result[key] = val
return result
使用法:
>>> d = MultiKeyDict(a=1, b=2)
>>> d['c', 'd'] = 3 # two keys for one value
>>> print d['c'], d['d']
3 3
>>> d['c'] = 4
>>> print d['d']
4
>>> d.add_keys('d', ('e',))
>>> d['e']
4
>>> d2 = MultiKeyDict.from_dict({ ('a', 'b'): 1 })
>>> d2['a'] = 2
>>> d2['b']
2