Python OOPS

A class is a blue print from which specific objects are created.Classes provide a means of bundling data and functionality together.

Objects

An Object is an instance of a Class.An object consists of:

State: It is represented by the attributes of an object. It also reflects the properties of an object.

Behavior: It is represented by the methods of an object. It also reflects the response of an object to other objects.

Identity: It gives a unique name to an object and enables one object to interact with other objects.

Example

class Dog:

	# A simple class
	# attribute
	attr1 = "mammal"
	attr2 = "dog"

	# A sample method
	def fun(self):
		print("I'm a", self.attr1)
		print(	"I'm a", self.attr2)
		
    # Object instantiation
    Rodger = Dog()

    # Accessing class attributes
    # and method through objects
    print(Rodger.attr1)
    Rodger.fun() 
    
    Output
    mammal
    I'm a mammal
    I'm a dog

Inheritance

A class can inherit attributes and behaviour methods from another class,called the superclass.A class which inherits from a superclass is called subclass or child class.

Example

 class Animal:

    # attribute and method of the parent class
    name = ""
    
    def eat(self):
        print("I can eat")

   # inherit from Animal
  class Dog( Animal):

    # new method in subclass
    def display(self):
       # access name attribute of superclass using self
        print("My name is ", self.name)

    # create an object of the subclass
    labrador = Dog()

    # access superclass attribute and method 
    labrador.name = "Rohu"
    labrador.eat()

    # call subclass method 
    labrador.display()
    
    Output
    I can eat
    My name is Rohu

Encapsulation

Binding the data and code together as a single unit is called encapsulation.Securing data by hiding the implementation details to user.

Abstraction

Hides the implementation details and only provides the functionality to the users.We can achieve abstraction using abstract classes and interfaces.