abstract classes in python code example

Example 1: abstract method python

from abc import ABC, abstractmethod
 
class AbstractClassExample(ABC):
 
	def __init__(self, value):
        self.value = value
        super().__init__()
    
    @abstractmethod
    def do_something(self):
        pass

Example 2: python abstract class

# Python program showing 
# abstract base class work 
  
from abc import ABC, abstractmethod 
class Animal(ABC): 
  
    def move(self): 
        pass
  
class Human(Animal): 
  
    def move(self): 
        print("I can walk and run") 
  
class Snake(Animal): 
  
    def move(self): 
        print("I can crawl") 
  
class Dog(Animal): 
  
    def move(self): 
        print("I can bark") 
  
class Lion(Animal): 
  
    def move(self): 
        print("I can roar") 
          
# Driver code 
R = Human() 
R.move() 
  
K = Snake() 
K.move() 
  
R = Dog() 
R.move() 
  
K = Lion() 
K.move() 

Output:

I can walk and run
I can crawl
I can bark
I can roar

Example 3: when we should use abstract class

When to use an abstract class
An abstract class is a good choice if we are using the inheritance concept since it provides a common base class implementation to derived classes.
An abstract class is also good if we want to declare non-public members. In an interface, all methods must be public.
If we want to add new methods in the future, then an abstract class is a better choice. Because if we add new methods to an interface, then all of the classes that already implemented that interface will have to be changed to implement the new methods.
If we want to create multiple versions of our component, create an abstract class. Abstract classes provide a simple and easy way to version our components. By updating the base class, all inheriting classes are automatically updated with the change. Interfaces, on the other hand, cannot be changed once created. If a new version of an interface is required, we must create a whole new interface.
Abstract classes have the advantage of allowing better forward compatibility. Once clients use an interface, we cannot change it; if they use an abstract class, we can still add behavior without breaking the existing code.
If we want to provide common, implemented functionality among all implementations of our component, use an abstract class. Abstract classes allow us to partially implement our class, whereas interfaces contain no implementation for any members.

Example 4: Abstraction example python

from abc import ABC,abstractclassmethod

class Parent(ABC):

    @abstractclassmethod
    def pqr(self):
        pass

class Child(Parent):

    def pqr(self):
        print("PQR")

obj = Child()
obj.pqr()