Python中的枚举类型示例介绍

Color = {
 'RED' : 1,
 'GREEN': 2,
 'BLUE' : 3,
}

class Color:
 RED = 1
 GREEN = 2
 BLUE = 3

from enum import Enum
class Color(Enum):
 red = 1
 green = 2
 blue = 3

> print(Color.red)
Color.red
> print(repr(Color.red))
<Color.red: 1>
> type(Color.red)
<Enum 'Color'>
> isinstance(Color.green, Color)
True

class Color(Enum):
 red = 1
 green = 2
 red = 3 # TypeError: Attempted to reuse key: 'red'

class Color(Enum):
 red = 1
 green = 2
 blue = 1

print(Color.red)    # Color.red
print(Color.blue)    # Color.red
print(Color.red is Color.blue)# True
print(Color(1))    # Color.red 在通过值获取枚举成员时，只能获取到第一个成员

from enum import Enum, unique
@unique
class Color(Enum):
 red = 1
 green = 2
 blue = 1 # ValueError: duplicate values found in <enum 'Color'>: blue -> red

print(Color['red']) # Color.red 通过成员名来获取成员

print(Color(1))  # Color.red 通过成员值来获取成员

member = Color.red
print(member.name) # red
print(member.value) # 1

for color in Color:
 print(color)

for color in Color.__members__.items():
 print(color)   # ('red', <Color.red: 1>)

Color.red is Color.red
Color.red is not Color.blue

Color.blue == Color.red
Color.blue != Color.red

Color.red < Color.blue # TypeError: unorderable types: Color() < Color()

from enum import IntEnum
class Shape(IntEnum):
 circle = 1
 square = 2

class Request(IntEnum):
 post = 1
 get = 2

print(Shape.circle == 1)   # True
print(Shape.circle < 3)    # True
print(Shape.circle == Request.post) # True
print(Shape.circle >= Request.post) # True