Python issubclass() Function

Python issubclass() is a built-in function that returns true if a class supplied as the first argument is the subclass of another class supplied as the second argument, else it returns false.

In Python, a class is considered as the subclass of itself.

Python issubclass() Syntax

issubclass(class, classinfo)

Python issubclass() takes two parameters.

• class (required) – a class that is to be checked
• classinfo (required) – a class, type or a tuple of classes or types

Here classinfo can be a tuple of class objects, in which case every entry in classinfo is checked. In any other case, a TypeError exception is raised.

So, the issubclass(class, classinfo) function will return true if and only if the class is a subclass of classinfo, else it will return false.

Python issubclass() Example

>>> class Car:
       pass
>>> class Buggati(Car):
       pass

>>> issubclass(Buggati, Car)
True
>>> issubclass(Car, Buggati)
False

>>> #checking if a class is subclass of itself
>>> issubclass(Car, Car)
True

Seems pretty much same as Python isinstance() function. So what is the difference?

Difference between Python issubclass() and isinstance()

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The difference is basic.

isinstance(object, classinfo) basically checks whether or not the object is an instance or subclass of classinfo.

Whereas, issubclass(class, classinfo) checks whether or not a class is subclass of classinfo.