CODEWITHSUNDEEP
pythonpython-3.xclass
Tim
Tim

Reputation: 99526

What is the relation between class "type" and specific types?

What is the relation between class type and specific types?

I thought that specific types were subclasses of type, but:

>>> type
<class 'type'>
>>> import builtins
>>> builtins.issubclass(type, object)
True
>>> builtins.issubclass(int, type)
False

Thanks.

Upvotes: 0

Views: 60

Answers (1)

Dimitris Fasarakis Hilliard
Dimitris Fasarakis Hilliard

Reputation: 160637

I thought that specific types were subclasses of type

They aren't. Every class is an instance of type; type acts as the class for classes. isinstance(class, type) returns True while issubclass correctly returns False.

A case where issubclass returns True is with custom meta-classes (class of classes) that actually inherit from type. For example, take EnumMeta:

>>> from enum import EnumMeta
>>> issubclass(EnumMeta, type)

This is True because EnumMeta has type as a base class (inherits from it):

>>> EnumMeta.__bases__
(type,)

if you looked its source up you'd see it's defined as class EnumMeta(type): ....

issubclass(type, object) returns True for everything because every single thing in Python is an object (meaning everything inherits from object).

Upvotes: 4

Related Questions