dict.get 可以返回默认值(例如， None ).如果我们以您的示例为例:

dict.get can return a default value (for example, None). If we take your examples:

dict_1 = {'A':4, 'C':5}
dict_2 = {'A':1, 'B':2, 'C':3}
dict_3 = {'B':6}
my_keys= ['A','B','C']

然后 dict_1.get('B'，None)是确保我们获得默认 None 值的方法.我们可以以相同的方式遍历所有键:

Then dict_1.get('B', None) is the way to make sure we get a default None value. We can loop across all keys the same way:

def dict_to_list(d, keys):
    return [d.get(key, None) for key in keys]

示例:

>>> dict_to_list(dict_1, my_keys)
[4, None, 5]
>>> dict_to_list(dict_2, my_keys)
[1, 2, 3]
>>> dict_to_list(dict_3, my_keys)
[None, 6, None]

无是默认参数，即使未明确指定，因此 dict_1.get('B')与 dict_1一样有效.get('B'，None)

None is the default argument even if it's not explicitly specified, so dict_1.get('B') would work just as well as dict_1.get('B', None)