03. A Beginner’s Guide to Python Object-Oriented Programming (OOP)

Introduction

Object-Oriented Programming (OOP) is a programming paradigm that uses “objects” – bundles of data and behavior – to build modular, reusable, and maintainable code. Python supports OOP, allowing you to define your own classes and create objects from them. Understanding OOP is essential for structuring larger applications effectively.

What Is OOP?

OOP stands for Object-Oriented Programming. In OOP, you model real-world entities using classes and objects. A class acts as a blueprint (template), and an object is an instance of that blueprint, with its own state (attributes) and behavior (methods).

Advantages of OOP

Provides a clear structure to programs
Makes code easier to maintain, reuse, and debug
Helps avoid repetition (follows the DRY principle)
Promotes building reusable components and modular code

Classes and Objects

Defining a Class and Creating Objects

You define a class using the class keyword, then create objects (instances) from that class.

class Car:

def __init__(self, make, model):

self.make = make

self.model = model

my_car = Car("Toyota", "Corolla")

print(my_car.make) # Toyota

print(my_car.model) # Corolla

Here, Car is the class; my_car is an object (instance) of that class.

The __init__() Method

The __init__() method is a special method (constructor) that is automatically called when an object is instantiated. It initializes the instance’s attributes.

The self Parameter

Inside class methods, you refer to the instance via the self parameter. It represents the object itself and gives you access to its attributes and methods.

Adding Methods

Methods are functions defined inside classes. They define behaviors or operations that objects of the class can perform.

class Person:

def __init__(self, name):

self.name = name

def greet(self):

print("Hello, my name is " + self.name)

p = Person("Alice")

p.greet()

Here, greet is a method. Objects call it using dot notation, e.g. p.greet().

Modifying and Deleting

You can modify attributes and even delete them using del:

p.age = 30 # add new attribute

p.name = "Bob" # modify existing attribute

del p.age # delete attribute

You can also delete entire objects:

del p

Inheritance and Reuse

Inheritance allows you to define a new class that inherits methods and attributes from an existing class. This promotes code reuse and hierarchical relationships.

class Animal:

def __init__(self, name):

self.name = name

def speak(self):

print("Animal sound")

class Dog(Animal):

def speak(self):

print("Woof")

d = Dog("Buddy")

d.speak() # Woof

You can override methods in subclasses to provide specialized behavior while retaining base class functionality.

Summary

Python’s object-oriented features let you model real-world concepts using classes and objects, encapsulating data and behavior together. By mastering class definitions, constructors, methods, inheritance, and object manipulation, you can design more robust, reusable, and maintainable programs.

03. A Beginners Guide to Python Object-Oriented Programming OOP

coldshadow44 on 2025-10-11

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