Python：枚举法

python枚举法方法很多，下面列举几种常见实现方式：

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1、自定义类

1、方法1

class SeriesEnum:
    one, two, three, four, five, six, seven, eight, nine, ten = range(10)
 
        
print(SeriesEnum.eight) # 7

2 方法2

class SeriesEnum():
    one     = 1
    two     = 2
    three   = 3
    four    = 4
 
 
print(SeriesEnum.one)   # 1

2、使用系统自带模块 Enum

1、Enum 默认键值value可重复，，键Key不能重复

from enum import Enum
class SeriesEnum(Enum):
    one     = 1
    two     = 2
    three   = 3
    four    = 4


print(SeriesEnum.one)          # SeriesEnum.one
print(SeriesEnum.one.value)    # 1

print(SeriesEnum['two'])       # SeriesEnum.two
print(SeriesEnum['two'].value) # 2
print(SeriesEnum(2))           # SeriesEnum.two

2、如果要求键不能重复,可以使用 unique

from enum import Enum, unique

@unique
class SeriesEnum(Enum):
    one     = 1
    two     = 2
    three   = 3
    four    = 4


print(SeriesEnum.one)       # SeriesEnum.one
print(SeriesEnum.one.value) # 1

3、第一个参数是枚举类的类名；第二个参数是一个元组

import enum
# 定义Number枚举类
Number = enum.Enum('Number', ('one', 'two', 'three', 'four'))

print(Number.One)       # Number.one
print(Number.one.value) # 1