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Difference between a Method and a Function

Difference between a Method and a Function

In programming, the terms "method" and "function" are often used to describe blocks of code that perform a specific task. While they share similarities, there are fundamental differences between them.


A function is a self-contained block of code that performs a particular task or calculation. It takes input, processes it, and produces an output. Functions are typically independent and can be used in various parts of a program.

Example of a Function (Python):

def add_numbers(a, b):
    return a + b

In this example, add_numbers is a function that takes two arguments a and b and returns their sum.


A method is similar to a function, but it is associated with an object or a class in object-oriented programming. Methods are defined within a class and operate on the data (attributes) of that class.

Example of a Method (Python):

class Rectangle:
    def __init__(self, width, height):
        self.width = width
        self.height = height

    def calculate_area(self):
        return self.width * self.height

In this example, calculate_area is a method defined within the Rectangle class. It operates on the attributes width and height of the class to calculate the area of the rectangle.

Key Differences

  1. Association: Functions are standalone and can be used anywhere in the program. Methods, on the other hand, are associated with objects or classes and operate on their attributes.

  2. Invocation: Functions are invoked by their names, and their arguments are passed explicitly. Methods are invoked on objects or instances of a class, and the object itself is implicitly passed as the first argument (often referred to as self in Python).

  3. Scope: Functions have their own scope, and they do not have access to attributes or data of specific objects. Methods, being associated with a class, have access to the data (attributes) of that class through the self parameter.

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