Inheritance Examples

Inheritance is the most important aspect of object-oriented programming which simulates the real world concept of inheritance. It specifies that the child object acquires all the properties and behaviors of the parent object.

By using inheritance, we can create a class which uses all the properties and behavior of another class. The new class is known as a derived class or child class, and the one whose properties are acquired is known as a base class or parent class.

It provides re-usability of the code.

Example 1:

#!/usr/bin/python3

class Parent:        # define parent class
   parentAttr = 100
   def __init__(self):
      print ("Calling parent constructor")

   def parentMethod(self):
      print ('Calling parent method')

   def setAttr(self, attr):
      Parent.parentAttr = attr

   def getAttr(self):
      print ("Parent attribute :", Parent.parentAttr)

class Child(Parent): # define child class
   def __init__(self):
      print ("Calling child constructor")

   def childMethod(self):
      print ('Calling child method')

c = Child()          # instance of child
c.childMethod()      # child calls its method
c.parentMethod()     # calls parent's method
c.setAttr(200)       # again call parent's method
c.getAttr()          # again call parent's method

Output:

Calling child constructor

Calling child method

Calling parent method

Parent attribute : 200

Example 2:

class Animal:  
    def speak(self):  
        print("Animal Speaking")  
#child class Dog inherits the base class Animal  
class Dog(Animal):  
    def bark(self):  
        print("dog barking")  
d = Dog()  
d.bark()  
d.speak()  

dog barking

Animal Speaking

Multi Level Inheritance:

Multi-Level inheritance is possible in python like other object-oriented languages. Multi-level inheritance is archived when a derived class inherits another derived class. There is no limit on the number of levels up to which, the multi-level inheritance is archived in python.

Example 3:

class Animal:  
    def speak(self):  
        print("Animal Speaking")  
#The child class Dog inherits the base class Animal  
class Dog(Animal):  
    def bark(self):  
        print("dog barking")  
#The child class Dogchild inherits another child class Dog  
class DogChild(Dog):  
    def eat(self):  
        print("Eating bread...")  
d = DogChild()  
d.bark()  
d.speak()  
d.eat() 

dog barking

Animal Speaking

Eating bread...