Difference between Module and Function in Python

Python is a high-level programming language. It is known for its optimization. It removes unnecessary aspects in programming and makes code effective. It is simple and easy to learn. Python allows to break the code into simpler parts so that it is easy to understand the code. It also allows us to reuse the code again hence reducing the number of lines of code. These are done using modules and functions.

All the classes, variables and functions that are important are collected and placed in a module so that they can be used at anytime and anywhere in programs. Modules can be used in multiple programs.

Function isolates a particular task from the entire program. It can be called whenever we need that task to perform.

Modules in Python

A module is a python file that contains functions, variables etc., in it and has .py extension. It is simply a python file that can be imported into another python program. The name of the module is the name of the python file itself.

As the number of lines of code goes on increasing in a program, it becomes difficult for us to understand that program. So, instead of writing all program in a single file, we can separate the code based on their functions into separate files that are referred as modules. This make the program clean and more readable. We can simply import those modules whenever needed using import statement. The syntax for importing module is given below.

import module_name 

Here, module_name represents the name that we have given to that module while saving it. Importing module doesn’t allow us to use the classes and functions in it directly. In order to access them, we use dot operator (.) as given below

module_name.function ()

Modules contains codes for specific task. This code can have functions, classes, variables etc., A module can be used in more than one program. Hence, it promotes code reusability and reduces the number of lines of code.

Advantages of Using Modules

  • Code reusability − One can use the same module number of times

  • Simplicity − Modules perform only a specific task hence making them simple

  • Scoping − Module has a separate namespace for its identifiers so it avoids collisions with other identifiers

Functions in Python

A function is a block of code that performs specific task. It executes only when it is called. Functions are classified into the following types −

Built-in Functions

Functions that are readily available within the python library are known as built-in functions. There are many built-in functions available. Print (), input (), list (), dict () etc., are some of the built-in functions in python.

User-defined Functions

Functions that are created and defined by the user are known as user defined functions. The def keyword is used to create a user defined function. One must call that function in order to use it. Function must be defined first before we call it. Otherwise it shows an error.

User-defined programs divide large program into smaller segments so that the code is easy to understand.

The syntax for defining a function is as shown below −

def function_name (parameters):

Here, function_name is the name we give to a function, parameters are the variables and statements represents the code and actual body of the function. Statements maybe a single or multiple lines of code. All the statements inside the function are indented to indicate that these statement blocks are present in a function.

The declared function can be called by specifying the name of the function followed by parenthesis as shown below:

function_name (arguments)

Arguments are the values that are passed to the parameters during a function call.

User-defined functions have the following advantages −

  • Code can be reused a number of times.

  • It prevents us from writing the same code again and again

  • Code becomes easy to understand if it is divided into multiple functions

  • A function call can be made anywhere in a program

Lambda Function

A function with no name is known as a lambda function. It is also known as Anonymous function. Lambda functions are created using the Lambda keyword. Lambda function can even accept another function as a parameter.

The syntax of the lambda function is given below −

lambda arguments: expression

Arguments are the values that are passed to the parameters during a function call and the expression is the statement being executed. It can have many arguments but the body of the lambda function can have only one statement in it.

Recursion Functions

Recursion functions are functions that calls itself repeatedly until the requirement is met.

Module vs Function in Python

The main difference between a module and a function is that a module is a collection of functions that are imported in multiple programs and can do various tasks. A function is a small block of code and separates itself from the entire code and have a fixed functionality. This function can be used anywhere within the same program whereas modules can be used in multiple programs.


Modules and functions both have one main goal that is code reusability. Functions are used for small tasks whereas modules are used for larger tasks as it allows various classes and functions in it. A module is used by importing it in another program where as a function is used by calling it.

Updated on: 21-Apr-2023

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