遵循Aaron Maenpaa提出的类Java枚举实现，我得出了以下结论。我们的想法是使它具有通用性和可解析性。

class Enum:
    #'''
    #Java like implementation for enums.
    #
    #Usage:
    #class Tool(Enum): name = 'Tool'
    #Tool.DRILL = Tool.register('drill')
    #Tool.HAMMER = Tool.register('hammer')
    #Tool.WRENCH = Tool.register('wrench')
    #'''

    name = 'Enum'    # Enum name
    _reg = dict([])   # Enum registered values

    @classmethod
    def register(cls, value):
        #'''
        #Registers a new value in this enum.
        #
        #@param value: New enum value.
        #
        #@return: New value wrapper instance.
        #'''
        inst = cls(value)
        cls._reg[value] = inst
        return inst

    @classmethod
    def parse(cls, value):
        #'''
        #Parses a value, returning the enum instance.
        #
        #@param value: Enum value.
        #
        #@return: Value corresp instance.        
        #'''
        return cls._reg.get(value)    

    def __init__(self, value):
        #'''
        #Constructor (only for internal use).
        #'''
        self.value = value

    def __str__(self):
        #'''
        #str() overload.
        #'''
        return self.value

    def __repr__(self):
        #'''
        #repr() overload.
        #'''
        return "<" + self.name + ": " + self.value + ">"

有趣的是，前几天我正好需要这个，但我找不到一个值得使用的实现……所以我自己写了:

import functools

class EnumValue(object):
    def __init__(self,name,value,type):
        self.__value=value
        self.__name=name
        self.Type=type
    def __str__(self):
        return self.__name
    def __repr__(self):#2.6 only... so change to what ever you need...
        return '{cls}({0!r},{1!r},{2})'.format(self.__name,self.__value,self.Type.__name__,cls=type(self).__name__)

    def __hash__(self):
        return hash(self.__value)
    def __nonzero__(self):
        return bool(self.__value)
    def __cmp__(self,other):
        if isinstance(other,EnumValue):
            return cmp(self.__value,other.__value)
        else:
            return cmp(self.__value,other)#hopefully their the same type... but who cares?
    def __or__(self,other):
        if other is None:
            return self
        elif type(self) is not type(other):
            raise TypeError()
        return EnumValue('{0.Name} | {1.Name}'.format(self,other),self.Value|other.Value,self.Type)
    def __and__(self,other):
        if other is None:
            return self
        elif type(self) is not type(other):
            raise TypeError()
        return EnumValue('{0.Name} & {1.Name}'.format(self,other),self.Value&other.Value,self.Type)
    def __contains__(self,other):
        if self.Value==other.Value:
            return True
        return bool(self&other)
    def __invert__(self):
        enumerables=self.Type.__enumerables__
        return functools.reduce(EnumValue.__or__,(enum for enum in enumerables.itervalues() if enum not in self))

    @property
    def Name(self):
        return self.__name

    @property
    def Value(self):
        return self.__value

class EnumMeta(type):
    @staticmethod
    def __addToReverseLookup(rev,value,newKeys,nextIter,force=True):
        if value in rev:
            forced,items=rev.get(value,(force,()) )
            if forced and force: #value was forced, so just append
                rev[value]=(True,items+newKeys)
            elif not forced:#move it to a new spot
                next=nextIter.next()
                EnumMeta.__addToReverseLookup(rev,next,items,nextIter,False)
                rev[value]=(force,newKeys)
            else: #not forcing this value
                next = nextIter.next()
                EnumMeta.__addToReverseLookup(rev,next,newKeys,nextIter,False)
                rev[value]=(force,newKeys)
        else:#set it and forget it
            rev[value]=(force,newKeys)
        return value

    def __init__(cls,name,bases,atts):
        classVars=vars(cls)
        enums = classVars.get('__enumerables__',None)
        nextIter = getattr(cls,'__nextitr__',itertools.count)()
        reverseLookup={}
        values={}

        if enums is not None:
            #build reverse lookup
            for item in enums:
                if isinstance(item,(tuple,list)):
                    items=list(item)
                    value=items.pop()
                    EnumMeta.__addToReverseLookup(reverseLookup,value,tuple(map(str,items)),nextIter)
                else:
                    value=nextIter.next()
                    value=EnumMeta.__addToReverseLookup(reverseLookup,value,(str(item),),nextIter,False)#add it to the reverse lookup, but don't force it to that value

            #build values and clean up reverse lookup
            for value,fkeys in reverseLookup.iteritems():
                f,keys=fkeys
                for key in keys:
                    enum=EnumValue(key,value,cls)
                    setattr(cls,key,enum)
                    values[key]=enum
                reverseLookup[value]=tuple(val for val in values.itervalues() if val.Value == value)
        setattr(cls,'__reverseLookup__',reverseLookup)
        setattr(cls,'__enumerables__',values)
        setattr(cls,'_Max',max([key for key in reverseLookup] or [0]))
        return super(EnumMeta,cls).__init__(name,bases,atts)

    def __iter__(cls):
        for enum in cls.__enumerables__.itervalues():
            yield enum
    def GetEnumByName(cls,name):
        return cls.__enumerables__.get(name,None)
    def GetEnumByValue(cls,value):
        return cls.__reverseLookup__.get(value,(None,))[0]

class Enum(object):
    __metaclass__=EnumMeta
    __enumerables__=None

class FlagEnum(Enum):
    @staticmethod
    def __nextitr__():
        yield 0
        for val in itertools.count():
            yield 2**val

def enum(name,*args):
    return EnumMeta(name,(Enum,),dict(__enumerables__=args))

接受或离开它，它做了我需要它做的:)

像这样使用它:

class Air(FlagEnum):
    __enumerables__=('None','Oxygen','Nitrogen','Hydrogen')

class Mammals(Enum):
    __enumerables__=('Bat','Whale',('Dog','Puppy',1),'Cat')
Bool = enum('Bool','Yes',('No',0))

我通常使用的解决方案是这个简单的函数来获取动态创建的类的实例。

def enum(names):
    "Create a simple enumeration having similarities to C."
    return type('enum', (), dict(map(reversed, enumerate(
        names.replace(',', ' ').split())), __slots__=()))()

使用它非常简单，只需使用包含想要引用的名称的字符串调用函数即可。

grade = enum('A B C D F')
state = enum('awake, sleeping, dead')

这些值只是整数，因此如果需要可以利用它(就像在C语言中一样)。

>>> grade.A
0
>>> grade.B
1
>>> grade.F == 4
True
>>> state.dead == 2
True

如果你需要数值，这是最快的方法:

dog, cat, rabbit = range(3)

在Python 3中。X你也可以在最后添加一个星号占位符，它将吸收范围内所有剩余的值，以防你不介意浪费内存和无法计数:

dog, cat, rabbit, horse, *_ = range(100)

从Python 3.4开始，正式支持枚举。您可以在Python 3.4文档页面上找到文档和示例。

枚举是使用类语法创建的，这使得它们很容易 读和写。中描述了另一种创建方法 功能的API。定义枚举，子类Enum如下所示:

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

这是我在这里找到的一个很好的Python食谱:http://code.activestate.com/recipes/577024-yet-another-enum-for-python/

def enum(typename, field_names):
    "Create a new enumeration type"

    if isinstance(field_names, str):
        field_names = field_names.replace(',', ' ').split()
    d = dict((reversed(nv) for nv in enumerate(field_names)), __slots__ = ())
    return type(typename, (object,), d)()

使用示例:

STATE = enum('STATE', 'GET_QUIZ, GET_VERSE, TEACH')

更多细节可以在食谱页面上找到。