Introduction to Object-Oriented Programming in Python

This article introduces the fundamentals of object‑oriented programming (OOP) in Python, beginning with the definition of a class as a blueprint for objects that share attributes and methods.

It explains class variables, which are defined within the class body and shared across all instances, and instance variables, which are created inside methods (typically __init__ ) and belong to each individual object.

Method overriding is described as the process of redefining a parent class method in a subclass to meet specific needs.

Inheritance is covered, showing how a derived class can reuse and extend the functionality of a base class, with notes on syntax, multiple inheritance, and the need to explicitly call the base class constructor.

Several code snippets illustrate these concepts, for example:

<code>#!/usr/bin/env python
class Price(object):
    a = 0
    def __init__(self):
        self.price = 100
        self.count = 0.7
    def price(self):
        new_price = self.price * self.count
        return new_price
p = Price()
print(p.price)
print(p.a)</code>

The article also discusses Python's built‑in class attributes such as __dict__ , __doc__ , __name__ , __module__ , and __bases__ , showing how to access them with another example.

Garbage collection in Python is explained, highlighting reference counting, the role of the reference counter, and how objects are reclaimed when their count reaches zero, including handling of cyclic references.

<code>a = 40  # create object
b = a   # increase reference count
c = [b] # increase reference count
del a   # decrease reference count
b = 100 # decrease reference count
c[0] = -1 # decrease reference count</code>

Additional sections demonstrate method overriding, private attributes (double‑underscore naming), and the distinction between protected (single underscore) and private members.

Overall, the article serves as a practical guide for beginners to understand and apply OOP principles in Python.