Python Object Oriented Programming

Python Object Oriented Programming, Classes, Objects, Methods, Constructors, Inheritance, Polymorphism, Abstraction, and Encapsulation.

Python Object-Oriented Programming

Object-oriented programming (OOP) refers to a type of computer programming in which programmers define the data type of a data structure, and also the types of operations (functions) that can be applied to the data structure.

Simula is considered the first object-oriented programming language, Smalltalk is considered the first truly object-oriented programming language.

The popular object-oriented languages are C++, Java, C#, PHP, Python, Ruby, Kotlin, etc.

Everything in Python is an object. An object has a state and behaviors. To create an object, you define a class first. And then, from the class, you can create one or more objects. The objects are instances of a class.

Python OOP Major Concepts and Principles:

Class
Object
Method
Inheritance
Polymorphism
Data Abstraction
Encapsulation

1. Class

A Class is like an object constructor or a “blueprint” for creating objects.

Create or Define a Python class:
To define a class, we use the class keyword followed by the class name. For example, the following defines a Country class:

class Country:
pass

Note: The pass statement is used as a placeholder for future code. When the pass statement is executed, nothing happens, but you avoid getting an error when an empty code is not allowed.

2. Object

The object is an entity that has a state and behavior. It may be any real-world object like a mouse, keyboard, chair, table, pen, etc. When we define a class, it needs to create an object to allocate the memory.

To create an object from the Country class, you use the class name followed by parentheses (), like calling a function:

Syntax:
objectname = Classname()

Example 1:

class bus:
def __init__(self,modelname, year):
self.modelname = modelname
self.year = year

def display(self):
print(self.modelname,self.year)

c1 = bus(“Tata”, 2016)
c1.display()

Example 2:

class myclass:
def add(self, num1, num2): #instance method
res = num1+num2
return res
def mul(num1, num2): #class method
res = num1*num2
return res

myobject = myclass()

x = myobject.add(10,76)
print(x)

x = myclass.mul(10,76)
print(x)

Note: The self is used to represent the instance of the class.