fromkeys：创建一个新的字典，使用可迭代的键和设置为value的值

Posted 2022-07-01 aizhinong

可迭代的键：字符串，列表，元组，字典等；value可以嵌套

dic = dict.fromkeys(1,2,3,([],[]))
print(dic)

dic[1][0].append(‘aike‘)
print(dic)

dic[2][0].append(‘艾克‘)
print(dic)

dic[2][1].append(‘183‘)
print(dic)

输出：

1: ([], []), 2: ([], []), 3: ([], [])
1: ([‘aike‘], []), 2: ([‘aike‘], []), 3: ([‘aike‘], [])
1: ([‘aike‘, ‘艾克‘], []), 2: ([‘aike‘, ‘艾克‘], []), 3: ([‘aike‘, ‘艾克‘], [])
1: ([‘aike‘, ‘艾克‘], [‘183‘]), 2: ([‘aike‘, ‘艾克‘], [‘183‘]), 3: ([‘aike‘, ‘艾克‘], [‘183‘])

 注：dic为字典，字典查询只有 for 、get和通过键查询，所以

dic[1][0]

dic[2][0]

当中的1和2对应的是dic的键值，例如：

dic = dict.fromkeys(‘a‘,‘b‘,‘c‘,([],[]))
print(dic)

dic[‘a‘][0].append(‘aike‘)
print(dic)

dic[‘b‘][0].append(‘艾克‘)
print(dic)

dic[‘c‘][1].append(‘183‘)
print(dic)

输出

‘a‘: ([], []), ‘c‘: ([], []), ‘b‘: ([], [])
‘a‘: ([‘aike‘], []), ‘c‘: ([‘aike‘], []), ‘b‘: ([‘aike‘], [])
‘a‘: ([‘aike‘, ‘艾克‘], []), ‘c‘: ([‘aike‘, ‘艾克‘], []), ‘b‘: ([‘aike‘, ‘艾克‘], [])
‘a‘: ([‘aike‘, ‘艾克‘], [‘183‘]), ‘c‘: ([‘aike‘, ‘艾克‘], [‘183‘]), ‘b‘: ([‘aike‘, ‘艾克‘], [‘183‘])