建立python的双向, 多重key值的dict
前端时间用python做音乐生成，需要用到可以双向查找的字典， 同时还希望词典中有重复的key值， 因而参考了stackoverflow上的代码， 将二者结合完成了所需
class Dictlist(dict):
def __setitem__(self, key, value):
try:
self[key]
except KeyError:
super(Dictlist, self).__setitem__(key, [])
self[key].append(value)
class BidirectionaDict(Dictlist):
def __setitem__(self, key, val):
Dictlist.__setitem__(self, key, val)
Dictlist.__setitem__(self, val, key)
def __delitem__(self, key):
Dictlist.__delitem__(self, self[key])
Dictlist.__delitem__(self, key)
Dictlist 完成多重key值实现
BidirectionDict 实现key和value的双向访问
测试：
> d = BidirectionalDict()
> d[‘test’] = 1
> d[‘test’] = 2
> d[‘test’] = 3
> d[‘train’] = 1
> d[‘train’] = 2
> d[‘test’]
[1, 2, 3]
> d[1]
[‘test’, ‘train’]