三元运算符的替代实现，一个衬里

Question

我有一个包含一些数据的字典，我想检查 obligatory_data_fields 的每个字段是否都包含在这个字典中。

obligatory_data_fields = ("nickname", "name", "picture", "updated_at", "email", "email_verified",
                                 "iss", "sub", "aud", "iat", "exp")


a = {
  "nickname": "a",
  "name": "abcd@email.gr",
  "picture": "https://s.gravatar.com/avatar/a.png",
  "updated_at": "2020-05-07T08:44:10.091Z",
  "email": "abcd@email.gr",
  "email_verified": 'false',
  "iss": "x",
  "sub": "x",
  "aud": "x",
  "iat": 1588841051,
  "exp": 1588877051
}

所以最明显的是这个：

for data in obligatory_data_fields:
    if data in a:
        pass
    else:
        print('missing ', data)

我想知道哪些是更好的 (efficient/faster) 实现方法。我的意思是像一个班轮[我知道我写的一个班轮是错误的]

例如pass if data in a else print('missing ', data) for data in obligatory_data_fields

Answer 1

如果只想验证，可以使用all:

>>> all(field in a for field in obligatory_data_fields)
True

如果您确实需要每个缺失字段的名称，您可以使用列表理解：

>>> missing = [field for field in obligatory_data_fields if field not in a]
>>> missing
[]

Answer 2

你也可以将字典的键值转换成一个集合，然后用集合差分得到缺失值：

>>> set(obligatory_data_fields)-set(a)
>>> set() # Empty set, every key in obligatory_data_fields is present in 'a'

三元运算符的替代实现，一个衬里

Alternative implementations with ternary operators, one liners

python

conditional-operator