Difference between Method and Function in Python

Here, key differences between Method and Function in Python are explained. Java is also an OOP language, but there is no concept of Function in it. But Python has both concept of Method and Function.

Python Method

1. Method is called by its name, but it is associated to an object (dependent).
2. A method definition always includes 'self' as its first parameter.
3. A method is implicitly passed to the object on which it is invoked.
4. It may or may not return any data.
5. A method can operate on the data (instance variables) that is contained by the corresponding class

Basic Method Structure in Python : 

# Basic Python method 
class class_name
    def method_name () :
        ......
        # method body
        ......   

Python 3 User-Defined Method : 

# Python 3  User-Defined  Method
class ABC :
    def method_abc (self):
        print("I am in method_abc of ABC class. ")
class_ref = ABC() # object of ABC class
class_ref.method_abc()

Output:

 I am in method_abc of ABC class

Python 3 Inbuilt method : 

import math
ceil_val = math.ceil(15.25)
print( "Ceiling value of 15.25 is : ", ceil_val) 

Output:

Ceiling value of 15.25 is :  16

Know more about Python ceil() and floor() method.

Functions

1. Function is block of code that is also called by its name. (independent)
2. The function can have different parameters or may not have any at all. If any data (parameters) are passed, they are passed explicitly.
3. It may or may not return any data.
4. Function does not deal with Class and its instance concept.

Basic Function Structure in Python : 

def function_name ( arg1, arg2, ...) :
    ......
    # function body
    ......   

Python 3 User-Defined Function : 

def Subtract (a, b):
    return (a-b)
print( Subtract(10, 12) ) # prints -2
print( Subtract(15, 6) ) # prints 9

Output:

-2
9

Python 3 Inbuilt Function : 

s = sum([5, 15, 2])
print( s ) # prints 22
mx = max(15, 6)
print( mx ) # prints 15

Output:

22
15

Know more about Python sum() function. Know more about Python min() or max() function.

Difference between method and function

1. Simply, function and method both look similar as they perform in almost similar way, but the key difference is the concept of 'Class and its Object'.
2. Functions can be called only by its name, as it is defined independently. But methods can't be called by its name only, we need to invoke the class by a reference of that class in which it is defined, i.e. method is defined within a class and hence they are dependent on that class.