Python issubclass()

The issubclass() function checks if the class argument (first argument) is a subclass of classinfo class (second argument).

The syntax of issubclass() is:

issubclass(class, classinfo)

1. issubclass() Parameters

issubclass() takes two parameters:

• class – class to be checked
• classinfo – class, type, or tuple of classes and types

2. Return Value from issubclass()

issubclass() returns:

• True if class is subclass of a class, or any element of the tuple
• False otherwise

3. Example: How issubclass() works?

class Polygon:
  def __init__(polygonType):
    print('Polygon is a ', polygonType)

class Triangle(Polygon):
  def __init__(self):

    Polygon.__init__('triangle')
    
print(issubclass(Triangle, Polygon))
print(issubclass(Triangle, list))
print(issubclass(Triangle, (list, Polygon)))
print(issubclass(Polygon, (list, Polygon)))

Output

True
False
True
True

It’s important to note that class is considered a subclass of itself.