On Feb 3, 9:06 pm, Jason <[EMAIL PROTECTED]> wrote: > On Feb 3, 8:36 pm, 7stud <[EMAIL PROTECTED]> wrote: > > > > > print dir(type) #__mro__ attribute is in here > > print dir(object) #no __mro__ attribute > > > class Mammals(object): > > pass > > class Dog(Mammals): > > pass > > > print issubclass(Dog, type) #False > > print Dog.__mro__ > > > --output:-- > > (<class '__main__.Dog'>, <class '__main__.Mammals'>, <type 'object'>) > > > The output suggests that Dog actually is a subclass of type--despite > > the fact that issubclass(Dog, type) returns False. In addition, the > > output of dir(type) and dir(object): > > > ['__base__', '__bases__', '__basicsize__', '__call__', '__class__', > > '__cmp__', '__delattr__', '__dict__', '__dictoffset__', '__doc__', > > '__flags__', '__getattribute__', '__hash__', '__init__', > > '__itemsize__', '__module__', '__mro__', '__name__', '__new__', > > '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', > > '__subclasses__', '__weakrefoffset__', 'mro'] > > > ['__class__', '__delattr__', '__doc__', '__getattribute__', > > '__hash__', '__init__', '__new__', '__reduce__', '__reduce_ex__', > > '__repr__', '__setattr__', '__str__'] > > > suggests that type inherits from object since type has all the same > > attributes as object plus some additional ones. That seems to > > indicate a hierarchy like this: > > > object > > | > > V > > type > > | > > V > > Mammals > > | > > V > > Dog > > > But then why does issubclass(Dog, type) return False? > > In your example, Mammal is directly derived from object, and Dog is > directly derived from Mammal. Dog isn't derived from type, so it > isn't considered a subclass.
>From the docs: issubclass(class, classinfo) Return true if class is a subclass (direct or indirect) of classinfo. -- http://mail.python.org/mailman/listinfo/python-list
