On Mon, 3 Apr 2023 at 17:57, Benedict Verhegghe <bver...@gmail.com> wrote: > > Well, it's not an object of type 'type' like the list or dict mentioned > by the OP, for which len() give a > TypeError: object of type 'type' has no len()
I'm not sure what you mean here. Enum is of type EnumMeta, which is a subclass of type. That means that, according to the normal rules of type hierarchy, Enum is indeed a type. Types add functionality that the parent type (with some Exceptions), so it should be no surprise that EnumMeta can add a __len__ method that type itself didn't have. > Any derived class of Enum will also return True for > isinstance(..., type). Yes, that is correct. Any subclass of Enum will also be a type, and will have a length. >>> class TestEnum(Enum): ... SPAM = 1 ... HAM = 2 ... >>> isinstance(TestEnum, type) True >>> len(TestEnum) 2 > Should the derived classes then neither have a > meaningful result for len()? Enum and derived classes hold a container > with a fixed set of values. It makes perfectly sense to ask for the > number of possible values, even when there are none. > Yeah, and I'm of the opinion that it's not a problem for Enum to have zero possible values, but to have the concept of values. Although it also wouldn't be a problem if it didn't. ChrisA _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/7BC4WQ5SN5AJBWOOWOUVWW7JK2RUSNDQ/ Code of Conduct: http://python.org/psf/codeofconduct/
