Python Classes and Objects Explained: A Beginner’s Guide to OOP

Introduction to Object-Oriented Programming in Python

Python is a powerful object-oriented programming language. Object-Oriented Programming (OOP) focuses on organizing code into reusable structures called objects, rather than relying solely on sequential instructions as in procedural programming.

OOP is especially useful for building complex applications because it improves code reusability, readability, and long-term maintainability.

Two core concepts in object-oriented programming are classes and objects:

• Class — A blueprint that defines the structure and behavior of an object.
• Object — A specific instance created from a class.

In this tutorial, you’ll learn how to define classes, create objects, use constructors, and work with multiple objects in Python.

Prerequisites

To follow this tutorial, you should have Python 3 installed and a working development environment. You can run the examples using a local machine or a remote server environment.

Understanding Python Classes

A class acts as a blueprint for creating objects. In Python, classes are defined using the class keyword.

class Shark:
    def swim(self):
        print("The shark is swimming.")

    def be_awesome(self):
        print("The shark is being awesome.")
  

Functions defined inside a class are called methods. Each method includes the self parameter, which refers to the current object instance.

Defining a class does not create an object—it only defines the structure for future objects.

Creating and Using Objects

An object is created by calling the class name followed by parentheses. Below, we create an instance of the Shark class.

sammy = Shark()
  

We can access object methods using the dot operator (.).

sammy.swim()
sammy.be_awesome()
  

The object sammy automatically passes itself to the methods through the self parameter.

The Constructor Method (__init__)

The constructor method, __init__, is executed automatically when a new object is created. It is commonly used to initialize object attributes.

class Shark:
    def __init__(self, name):
        self.name = name
  

We can now use the name attribute inside other methods.

class Shark:
    def __init__(self, name):
        self.name = name

    def swim(self):
        print(self.name + " is swimming.")

    def be_awesome(self):
        print(self.name + " is being awesome.")
  

When creating an object, we pass the required parameters directly to the class.

sammy = Shark("Sammy")
  

Working with Multiple Objects

One of the major benefits of classes is the ability to create multiple objects from the same blueprint.

sammy = Shark("Sammy")
stevie = Shark("Stevie")

sammy.be_awesome()
stevie.swim()
  

Each object maintains its own state while sharing the same structure and behavior.

Conclusion

In this guide, you learned the fundamentals of object-oriented programming in Python, including classes, objects, constructors, and multiple instances.

Understanding OOP is essential for building scalable, maintainable Python applications, especially as projects grow in size and complexity.