Python Abstraction

Abstraction helps to abstract or hide the internal logic of a function from the end user. User knows "what the function does" but no idea on "how it does". It reduces the overall application complexity and enhance application security. The abc module in python helps to achieve the abstraction in the program

Abstract Class

Below is an example for abstraction which is implemented with the help of abstract classes and methods

#Abstract class
from abc import ABC, abstractmethod

class Shapes(ABC):
    @abstractmethod
    def number_of_sides():
        pass

class Square(Shapes):
    def number_of_sides(self):
        print("Square - Four Sides")

class Triangle(Shapes):
    def number_of_sides(self):
        print("Triangle - Three Sides")

class Pentagon(Shapes):
    def number_of_sides(self):
        print("Pentagon - Five Sides")

square = Square()
square.number_of_sides()

triangle = Triangle()
triangle.number_of_sides()

pentagon = Pentagon()
pentagon.number_of_sides()

Output

Square - Four Sides
Triangle - Three Sides
Pentagon - Five Sides

Abstract Methods

Shaped(ABC) forces the child class to implement its abstract method.

#Abstract Method
from abc import ABC, abstractmethod

class Shapes(ABC):
    @abstractmethod
    def number_of_sides():
        pass

class Circle(Shapes):
    def print_shape(self):
        print("I am circle")

circle = Circle()
circle.print_shape()

Output:

Traceback (most recent call last):
File "<string>", line 13, in <module>
TypeError: Can't instantiate abstract class Circle with abstract methods number_of_sides

To overcome this error, abstract methods helps to avoid the compulsory implementation

#Abstract Methods
from abc import ABC, abstractmethod

#ABC - NotInherited
class Shapes():
    @abstractmethod
    def number_of_sides():
        pass

class Circle(Shapes):
    def print_shape(self):
        print("I am circle")

circle = Circle()
circle.print_shape()

Output

I am circle