Chapters 13 : Mastering Object-Oriented Programming

Introduction

As software applications grow larger and more complex, writing code as a collection of simple functions becomes difficult to manage. Developers need a structured way to organize code, reuse functionality, and build scalable applications. This is where Object-Oriented Programming (OOP), Modules, and Packages become essential.

Object-Oriented Programming allows developers to model real-world entities as objects, making code easier to maintain, extend, and understand. Modules and packages further improve organization by dividing large applications into manageable components.

In these chapters, you will learn the core principles of OOP, including classes, objects, constructors, inheritance, polymorphism, encapsulation, and abstraction. You will also explore modules and packages, which help organize Python projects into reusable and maintainable units.

Chapter 13: Object-Oriented Programming (OOP)

Object-Oriented Programming is a programming paradigm that organizes code around objects rather than functions and procedures.

An object can represent a real-world entity such as a student, car, bank account, employee, or product.

Classes

A class is a blueprint or template used to create objects. It defines the attributes and behaviors that objects will possess.

Creating a Class

class Student:
    pass

This class currently contains no attributes or methods but serves as a blueprint.

Class Example

class Student:
    name = "John"
    age = 20

The class defines two attributes: name and age.

Objects

An object is an instance of a class.

Creating an Object

class Student:
    name = "John"

student1 = Student()

Here, student1 is an object created from the Student class.

Accessing Attributes

print(student1.name)

Output:

John

Constructors

A constructor is a special method that automatically executes when an object is created.

In Python, constructors are defined using the **init**() method.

Constructor Example

class Student:
    def **init**(self, name, age):
        self.name = name
        self.age = age

student1 = Student("Alice", 21)
print(student1.name)

The constructor initializes object data when the object is created.

Attributes

Attributes are variables that belong to a class or object.

Instance Attributes

class Car:
    def **init**(self, brand, model):
        self.brand = brand
        self.model = model

Each object can have its own unique values.

Accessing Attributes

car1 = Car("Toyota