python模拟enum枚举类型

python中没有enum枚举类型，可能python认为这玩意压根就没用，下面列举了三种方法模拟enum枚举类型

方法1.&nbsp使用自定义类

class Numbers(object):
    ONE = 1
    TWO = 2
    THREE = 3
 
assert Numbers.ONE == 1
assert Numbers.TWO == 2
assert Numbers.THREE == 3

方法2：使用函数动态创建类

def enum(**enums):
    return type('Enum', (object,), enums)
 
Numbers = enum(ONE=1, TWO=2, THREE=3)
 
assert Numbers.ONE == 1
assert Numbers.TWO == 2
assert Numbers.THREE == 3

方法3：创建一个从python的集合扩展来的对象

class Enum(set):
    def __getattr__(self, name):
        if name in self:
            return name
        raise AttributeError
 
Numbers = Enum( "ONE TWO THREE".split() )
 
error = False
try:
    print Numbers.ONE
    print Numbers.TWO
    print Numbers.THREE
except:
    error = True
assert error == False
 
try:
    print Numbers.FOUR
except:
    error = True
assert error == True