Inheritance in Python

The process of inheriting the properties of the parent class into a child class is called inheritance. The existing class is called a base class or parent class and the new class is called a subclass or child class or derived class.

In this Python lesson, you will learn inheritance, method overloading, method overriding, types of inheritance, and MRO (Method Resolution Order).

In Object-oriented programming, inheritance is an important aspect. The main purpose of inheritance is the reusability of code because we can use the existing class to create a new class instead of creating it from scratch.

In inheritance, the child class acquires all the data members, properties, and functions from the parent class. Also, a child class can also provide its specific implementation to the methods of the parent class.

For example, In the real world, Car is a sub-class of a Vehicle class. We can create a Car by inheriting the properties of a Vehicle such as Wheels, Colors, Fuel tank, engine, and add extra properties in Car as required.

Syntax

class BaseClass:
  Body of base class
class DerivedClass(BaseClass):
  Body of derived classCode language: Python (python)

Types Of Inheritance

In Python, based upon the number of child and parent classes involved, there are five types of inheritance. The type of inheritance are listed below:

1. Single inheritance
2. Multiple Inheritance
3. Multilevel inheritance
4. Hierarchical Inheritance
5. Hybrid Inheritance

Now let’s see each in detail with an example.

Single Inheritance

In single inheritance, a child class inherits from a single-parent class. Here is one child class and one parent class.

Example

Let’s create one parent class called ClassOne and one child class called ClassTwo to implement single inheritance.

# Base class
class Vehicle:
    def Vehicle_info(self):
        print('Inside Vehicle class')

# Child class
class Car(Vehicle):
    def car_info(self):
        print('Inside Car class')

# Create object of Car
car = Car()

# access Vehicle's info using car object
car.Vehicle_info()
car.car_info()
Code language: Python (python)

Output

Inside Vehicle class
Inside Car class

Multiple Inheritance

In multiple inheritance, one child class can inherit from multiple parent classes. So here is one child class and multiple parent classes.

Example

# Parent class 1
class Person:
    def person_info(self, name, age):
        print('Inside Person class')
        print('Name:', name, 'Age:', age)

# Parent class 2
class Company:
    def company_info(self, company_name, location):
        print('Inside Company class')
        print('Name:', company_name, 'location:', location)

# Child class
class Employee(Person, Company):
    def Employee_info(self, salary, skill):
        print('Inside Employee class')
        print('Salary:', salary, 'Skill:', skill)

# Create object of Employee
emp = Employee()

# access data
emp.person_info('Jessa', 28)
emp.company_info('Google', 'Atlanta')
emp.Employee_info(12000, 'Machine Learning')
Code language: Python (python)

Output

Inside Person class
Name: Jessa Age: 28

Inside Company class
Name: Google location: Atlanta

Inside Employee class
Salary: 12000 Skill: Machine Learning

In the above example, we created two parent classes Person and Company respectively. Then we create one child called Employee which inherit from Person and Company classes.

Multilevel inheritance

In multilevel inheritance, a class inherits from a child class or derived class. Suppose three classes A, B, C. A is the superclass, B is the child class of A, C is the child class of B. In other words, we can say a chain of classes is called multilevel inheritance.

Example

# Base class
class Vehicle:
    def Vehicle_info(self):
        print('Inside Vehicle class')

# Child class
class Car(Vehicle):
    def car_info(self):
        print('Inside Car class')

# Child class
class SportsCar(Car):
    def sports_car_info(self):
        print('Inside SportsCar class')

# Create object of SportsCar
s_car = SportsCar()

# access Vehicle's and Car info using SportsCar object
s_car.Vehicle_info()
s_car.car_info()
s_car.sports_car_info()
Code language: Python (python)

Output

Inside Vehicle class
Inside Car class
Inside SportsCar class

In the above example, we can see there are three classes named Vehicle, Car, SportsCar. Vehicle is the superclass, Car is a child of Vehicle, SportsCar is a child of Car. So we can see the chaining of classes.

Hierarchical Inheritance

In Hierarchical inheritance, more than one child class is derived from a single parent class. In other words, we can say one parent class and multiple child classes.