Python Polymorphism

Polymorphism = "Poly" + "morphism"

  • "Poly" means Many
  • "morphism" means combined form

Polymorphism simply means that we can call the same method name with different/same parameters, and depending on the parameters, it will do different things.

It can also be defined as follows

Polymorphism can be defined as different objects acts differently for same interface(i.e functions, methods, classes)

Let's look at an example

class Rectangle:
    def __init__(self, length, width):
        self.length = length
        self.width = width

    def area(self):
        return self.length * self.width

class Circle:
    def __init__(self, radius):
        self.radius = radius

    def area(self):
        return 3.14 * (self.radius ** 2)

def print_area(shape):
    print(f"type: {shape.__class__.__name__}")
    print(f"area: {shape.area()}")

rect = Rectangle(10, 20)
# ouput:
# type: Rectangle
# area: 200
circle = Circle(10)
# ouput: 
# type: Circle
# area: 314.0
  • In the above code, we have two objects which are different types but has same method name area()
  • When we call area on method area() on each object it calculated differently and gave the output.
  • we can say print_area is a polymorphic function.

Note: we use method overloading & method overriding to achieve polymorphism in most of the cases.