有没有一种专用的方法来获取python`Enum`中的项目数？

Question

Say I have such a python Enum class:

from enum import Enum

class Mood(Enum):
    red = 0
    green = 1
    blue = 2

Is there a natural way to get the total number of items in Mood ? (like without having to iterate over it, or to add an extra n item, or an extra n classproperty , etc .)

Does the enum module provide such a functionality?

Answer 1

Yes. Enum s have several extra abilities that normal classes do not:

class Example(Enum):
    this = 1
    that = 2
    dupe = 1
    those = 3

print(len(Example))  # duplicates are not counted
# 3

print(list(Example))
# [<Example.this: 1>, <Example.that: 2>, <Example.those: 3>]

print(Example['this'])
# Example.this

print(Example['dupe'])
# Example.this

print(Example(1))
# Example.this

Answer 2

您尝试过print(len(Mood))吗？