Types of Methods in Python

In Python, methods define the behavior of a class and determine how data is accessed and modified. Based on what they operate on—object data, class-level data, or no data at all—Python provides three types of methods:

Instance Methods
Class Methods
Static Methods

Variables and Their Scope

Before exploring method types, it is important to understand variable scope:

Class_Instance_Variables

Instance Methods

What Are Instance Methods?

Instance methods are the most common type of methods
They use self as the first parameter
They operate on instance variables
Each object maintains its own independent state

Example

class Computer:
    brand = "Telusko AI"

    def __init__(self, cpu, ram, ssd):
        print("init called")
        self.cpu = cpu
        self.ram = ram
        self.ssd = ssd

    def config(self):
        print("config :", self.cpu, self.ram, self.ssd)

com1 = Computer("i5", "16GB", "512GB")
com2 = Computer("i9", "96GB", "2TB")

com1.config()
com2.config()
print(Computer.brand)

Output

init called
init called
config : i5 16GB 512GB
config : i9 96GB 2TB
Telusko AI

Key Points

self refers to the current object
Instance methods work with object-specific data
Changes affect only that object

Class Methods

What Are Class Methods?

Defined using the @classmethod decorator
Use cls as the first parameter (by convention)
Work with class variables
The class itself is passed automatically, not an object

Example

class Computer:
    brand = "Telusko AI"

    def __init__(self, cpu, ram, ssd):
        self.cpu = cpu
        self.ram = ram
        self.ssd = ssd

    def config(self):
        print("config :", self.cpu, self.ram, self.ssd)

    @classmethod
    def info(cls):
        return cls.brand

print(Computer.info())

Output

Telusko AI

Key Points

Class methods operate on shared data
Modifying class variables affects all objects
Often used for factory methods or class-level information

Static Methods

What Are Static Methods?

Defined using the @staticmethod decorator
Do not receive self or cls
Independent of both object and class state
Used as utility or helper functions

Example

class Computer:
    @staticmethod
    def gb_to_bytes(gb):
        return gb * (1024 ** 3)

print(Computer.gb_to_bytes(16))

Output

17179869184

Key Points

No access to instance or class variables
Logically related to the class
Improves code organization and readability

Impact of Variable Scope

Modifying a class variable using the class name affects all objects
Modifying an instance variable using self affects only that object
Instance and class variables exist in separate namespaces

Method_Types

Summary

Python provides three types of methods: instance, class, and static.
Instance methods operate on object-specific (instance) data using self.
Class methods operate on shared class-level data using cls.
Static methods act as utility functions, independent of class and object state.
Using the appropriate method type results in cleaner, more maintainable, and well-structured object-oriented code.

Written By: Muskan Garg

Types of Methods

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