Question

如何初始化一个字典与列表和空值在Python中的钥匙

Answer 1

1. dict.fromkeys([1, 2, 3, 4])这实际上是一个所以它适用于字典-子类（如collections.defaultdict）为好。可选的第二个参数指定的键（默认为值None。）

2.
dict.fromkeys(keys, None)

3.
>>> keys = [1,2,3,5,6,7]
>>> {key: None for key in keys}
{1: None, 2: None, 3: None, 5: None, 6: None, 7: None}

4.
d = {}
for i in list:
d[i] = None