Python的“二维”字典 (two-dimension dictionary)定义与实现方法

dict_2d = {'a': {'a': 1, 'b': 3}, 'b': {'a': 6}}

dict_2d['a']['b']

dict_1d = dict()
dict_1d['a'] = 1

dict_1d.update({'a': 1})

dict_2d['a']['c'] = 8

def addtwodimdict(thedict, key_a, key_b, val):
  if key_a in adic:
    thedict[key_a].update({key_b: val})
  else:
    thedict.update({key_a:{key_b: val}})

mapdict = dict()
addtwodimdict(mapdict, 'Beijing', 'Guangzhou', 1897)
addtwodimdict(mapdict, 'Chengdu', 'Guangzhou', 1243)
addtwodimdict(mapdict, 'Guangzhou', 'Shanghai', 1212)
addtwodimdict(mapdict, 'Beijing', 'Chengdu', 1516)
addtwodimdict(mapdict, 'Chengdu', 'Shanghai', 1657)
addtwodimdict(mapdict, 'Beijing', 'Shanghai', 1075)
print 'The distance between Chengdu and Guangzhou is '，mapdict['Chengdu']['Guangzhou']