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Method overriding is a feature of any object-oriented programming language that allows a subclass or child class to implement a method that is already provided by one of its super-classes or parent classes. When a method in a subclass has the same name, parameters or signature, and return type (or sub-type) as a method in its super-class, the subclass method is said to override the method in the super-class.

To override a function, the following conditions must be met:

• There should be inheritance. Within a class, function overriding is not possible. We must create a child class from a parent class.
• The redefined function in the child class should have the same signature as the parent class, i.e. the same number of parameters.

Key Features of Python Method Overriding:

The following are some of the key features and benefits of Python method overriding:

• The concept of method overriding is derived from object-oriented programming.
• Method overriding allows us to change the implementation of a function defined in the parent class in the child class.
• The inheritance mechanism includes method overriding.
• Method overriding avoids code duplication while also improving the code by adding some extra properties.

Python Method Overriding Example:

# Parent class 
class Shape:
    # properties 
    data1 = "abc"

    # function no_of_sides 
    def no_of_sides(self):
        print("My sides need to be defined. I am from shape class.")

    # function two_dimensional 
    def two_dimensional(self):
        print("I am a 2D object. I am from shape class")

class Square (Shape):
    data2 = "XYZ"

    def no_of_sides (self):
        print("I have 4 sides. I am from Square class")

    def color(self):
        print("I have teal color. I am from Square class.")

# Create an object of Square class 
sq = Square() 
# Override the no_of_sides of parent class 
sq.no_of_sides() 
# Will inherit this method from the parent class
sq.two_dimensional() 
# It's own method color 
sq.color()

Here,

• no_of_sides is the overridden method in the Shape class, since the Square class method – no_of_sides() will be overriding it (adding its own implementation).
• wo_dimensional is inherited by the sub_class(hence inherited method)
• color is a new method added in the Square class.
• data1 & data2 are individual properties of the classes.
• In the child class – Square, we have overridden the method no_of_sides() adding our implementation.

Output:

I have 4 sides. I am from Square class
I am a 2D object. I am from shape class
I have teal color. I am from Square class.

Note: also read about Access Modifiers in Python

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