The method overriding in Python means creating two methods with the same name but differ in the programming logic. The concept of Method overriding allows us to change or override the Parent Class function in the Child Class.
In Python, to override a method, you have to meet certain conditions and they are:
- You can’t override a method within the same class. It means, you have to do it in the child class using the Inheritance concept.
- To override the Parent Class method, you have to create a method in the Child class with same name and same number of parameters.
For example, if you have the function that calculated the Salary Hike for all the employees in an Organisation. But certain department or people get different percentage. In this scenario, you can override the existing method in the Department class and write your own logic.
In this article, we will show you, how to perform Method Overriding in Python Programming Language with an example.
Python Method Overriding Example
In this example, we created an employee class, which contains a message method that prints a message. Next, we created a department class that inherits from Employee class. Within this class, we created a method with the same name message with different print message.
This is a simple demonstration of Python Method Overriding. Here, we are just overriding the message. Next, we created an Object for Employee and Department class and calling that message function.
# Python Method Overriding
class Employee:
def message(self):
print('This message is from Employee Class')
class Department(Employee):
def message(self):
print('This Department class is inherited from Employee')
emp = Employee()
emp.message()
print('------------')
dept = Department()
dept.message()OUTPUT
You can see from the above screenshot, emp object is printing a string from Employee class message function. Where as, dept.message() is printing test from Department class.
In this example, we created one more class that is inherited from Employee class. Next, we are overriding the message function from this Sales class as well.
class Employee:
def message(self):
print('This message is from Employee Class')
class Department(Employee):
def message(self):
print('This Department class is inherited from Employee')
class Sales(Employee):
def message(self):
print('This Sales class is inherited from Employee')
emp = Employee()
emp.message()
print('------------')
dept = Department()
dept.message()
print('------------')
sl = Sales()
sl.message()OUTPUT
Python Method Overriding in Multiple Inheritance
This example shows you, how to perform method overloading in multiple inheritance situation. I suggest you to refer to Python Inheritance article to understand the inheritance.
class Employee:
def message(self):
print('This message is from Employee Class')
class Department(Employee):
def message(self):
print('This Department class is inherited from Employee')
class Sales(Department):
def message(self):
print('This Sales class is inherited from Employee')
emp = Employee()
emp.message()
print('------------')
dept = Department()
dept.message()
print('------------')
sl = Sales()
sl.message()OUTPUT
Python Method Overriding with arguments
Until now, we are only changing the print statement. I mean, overriding methods without any arguments. In this example, we created an add method with two arguments in parent class and three arguments in child class.
class Employee:
def add(self, a, b):
print('The Sum of Two = ', a + b)
class Department(Employee):
def add(self, a, b, c):
print('The Sum of Three = ', a + b + c)
emp = Employee()
emp.add(10, 20)
print('------------')
dept = Department()
dept.add(50, 130, 90)OUTPUT
Calling Parent Function within the Method Overriding in Python
In this Python method overriding example, we are calling the parent function from the overriding method.
class Employee:
def message(self):
print('This message is from Employee Class')
class Department(Employee):
def message(self):
Employee.message(self)
print('This Department class is inherited from Employee')
emp = Employee()
emp.message()
print('------------')
dept = Department()
dept.message()OUTPUT
As you can see from the above screenshot, both are giving different results based on the object. Here, Employee.message(self) calls the print(‘This message is from Employee Class’) statement and prints the message within that print function.
Instead of using the the class name, you can use the super() function to call the parent class method. This example show you the same.
class Employee:
def message(self):
print('This message is from Employee Class')
class Department(Employee):
def message(self):
super().message()
print('This Department class is inherited from Employee')
emp = Employee()
emp.message()
print('------------')
dept = Department()
dept.message()OUTPUT
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