How to Create a Class in Python: Syntax and Examples

To create a class in Python, use the class keyword followed by the class name and a colon. Inside the class, define methods like __init__ to initialize objects and other functions to add behavior.

Syntax

A Python class is defined using the class keyword followed by the class name and a colon. Inside, you define methods, including the special __init__ method which runs when you create an object. Methods always have self as the first parameter to access the object's data.

python

class ClassName:
    def __init__(self, parameters):
        # initialize object attributes
        self.attribute = parameters

    def method_name(self):
        # method code here
        pass

Example

This example shows how to create a simple Car class with an __init__ method to set the car's brand and a method to display it.

python

class Car:
    def __init__(self, brand):
        self.brand = brand

    def show_brand(self):
        print(f"This car is a {self.brand}.")

my_car = Car("Toyota")
my_car.show_brand()

Output

This car is a Toyota.

Common Pitfalls

Common mistakes include forgetting the self parameter in methods, which causes errors when accessing object attributes. Another is not using the __init__ method properly to initialize objects, leading to missing data.

python

class Wrong:
    def __init__(self, brand):  # Added self
        self.brand = brand

class Right:
    def __init__(self, brand):  # Correct
        self.brand = brand

Quick Reference

Term	Description
class	Keyword to define a class
__init__	Special method to initialize new objects
self	Represents the instance of the class
method	Function defined inside a class
attribute	Variable that belongs to an object

Key Takeaways

Use the class keyword followed by the class name and a colon to create a class.

Define the __init__ method with self to initialize object attributes.

Always include self as the first parameter in methods to access object data.

Forget self or __init__ causes common errors when creating classes.

Use methods inside classes to add behavior to your objects.