Python中Enum使用的几点注意事项

class Mood(Enum):
    FUNKY = 1
    HAPPY = 3
    def describe(self):
        # self is the member here
        return self.name, self.value
    def __str__(self):
        return 'my custom str! {0}'.format(self.value)
    @classmethod
    def favorite_mood(cls):
        # cls here is the enumeration
        return cls.HAPPY

>>> Mood.favorite_mood()
<Mood.HAPPY: 3>
>>> Mood.HAPPY.describe()
('HAPPY', 3)
>>> str(Mood.FUNKY)
'my custom str! 1'

from enum import Enum
class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3

>>> type(Color.RED)
<enum 'Color'>
>>> isinstance(Color.GREEN, Color)
True

>>> Color.RED == 1
False
>>> Color.RED.value == 1
False

>>> Color.RED.name == "RED"
True

>>> class MoreColor(Color):
...     PINK = 17
...
Traceback (most recent call last):
...
TypeError: MoreColor: cannot extend enumeration 'Color'

class Foo(Enum):
    def some_behavior(self):
        pass

class Bar(Foo):
    HAPPY = 1
    SAD = 2