Object Oriented Programming (OOP) in Python

Object Oriented Programming (OOP) is a programming approach that organizes code into objects and classes. Python fully supports OOP, making programs more modular, reusable, scalable, and easy to maintain.

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Why Use OOP in Python?

• Better code organization
• Reusability of code
• Easy maintenance and updates
• Real-world problem modeling
• Widely used in automation frameworks and applications

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Basic OOP Concepts in Python

Python OOP is based on four main principles:

1. Class
2. Object
3. Encapsulation
4. Inheritance
5. Polymorphism
6. Abstraction

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1. Class in Python

A class is a blueprint or template used to create objects. It defines variables (attributes) and functions (methods).

class Car:
    brand = "Toyota"

    def start(self):
        print("Car started")

Here:

• Car is a class
• brand is a class variable
• start() is a method

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2. Object in Python

An object is an instance of a class. It represents a real-world entity created using a class.

my_car = Car()
my_car.start()
print(my_car.brand)

Output:

Car started
Toyota

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3. The __init__() Constructor

The __init__() method is a special constructor that runs automatically when an object is created.

class Employee:
    def __init__(self, name, salary):
        self.name = name
        self.salary = salary

    def show_details(self):
        print(self.name, self.salary)

emp1 = Employee("Chandan", 50000)
emp1.show_details()

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4. Encapsulation

Encapsulation means hiding internal data and allowing access through methods only.

class Account:
    def __init__(self, balance):
        self.__balance = balance   # private variable

    def get_balance(self):
        return self.__balance

Note: Variables starting with __ are private.

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5. Inheritance

Inheritance allows a class to reuse properties and methods of another class.

class Animal:
    def speak(self):
        print("Animal speaks")

class Dog(Animal):
    def bark(self):
        print("Dog barks")

dog = Dog()
dog.speak()
dog.bark()

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6. Polymorphism

Polymorphism means same method name but different behavior.

class Bird:
    def fly(self):
        print("Bird can fly")

class Penguin(Bird):
    def fly(self):
        print("Penguin cannot fly")

b = Bird()
p = Penguin()

b.fly()
p.fly()

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7. Abstraction

Abstraction hides implementation details and shows only essential features. Python uses abstract classes for abstraction.

from abc import ABC, abstractmethod

class Vehicle(ABC):

    @abstractmethod
    def start(self):
        pass

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Real-World Example (Automation Testing)

class Browser:
    def open(self):
        print("Opening browser")

class Chrome(Browser):
    def open(self):
        print("Opening Chrome Browser")

This approach is widely used in Selenium and Robot Framework projects.

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Advantages of OOP in Python

• Code reusability
• Easy debugging
• Improved security
• Better scalability

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OOP Interview Questions

• What is OOP?
• Difference between class and object
• Explain encapsulation with example
• What is method overriding?
• Explain inheritance in Python

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Conclusion

Object Oriented Programming in Python helps developers write clean, reusable, and scalable code. Understanding OOP is mandatory for Python developers, automation testers, and framework designers.

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