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copied!<p>It's funny, I just had a need for this the other day and I couldnt find an implementation worth using... so I wrote my own:</p> <pre><code>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)) </code></pre> <p>Take it or leave it, it did what I needed it to do :)</p> <p>Use it like:</p> <pre><code>class Air(FlagEnum): __enumerables__=('None','Oxygen','Nitrogen','Hydrogen') class Mammals(Enum): __enumerables__=('Bat','Whale',('Dog','Puppy',1),'Cat') Bool = enum('Bool','Yes',('No',0)) </code></pre>

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