Python Modules use to enhance the capabilities of Python Programming Language. Though Python functions are very much there to help us a lot. A lits of built-in Python functions are as follows

Python module contains the reusable functions for different needs. In order to use a function of a Python module, import that function

import <module_name>

Importing Whole Modules

import math

Import module and rename it

import math as m

import single function from a module

import math.factorial
or
from math import factorial

How to find out modules

Use help command like this at python prompt to display all the available modules in Python

>>>help('modules')

When the above code is executed, shows

if you want to know the functions available in any modules

>>>import math
>>>dir(math)

Now this is a huge collection of functions. it is almost impossible for anyone to learn all this information by heart. so to know the functionality of any module function, use the help function again

import math
>>>help(math.factorial)

The output of the above help function is

>>> help(math.factorial)
Help on built-in function factorial in module math:

factorial(x, /)
    Find x!.
    
    Raise a ValueError if x is negative or non-integral.

How to use the module function in Python Program

There are several methods to use module functions. Some of them are as follows

1st method: Import whole module, use the function with the module name.

import math
n = int(input('Enter any number :'))
result = math.factorial(n)
print(' Result :',result)

2nd method:- Import module as a new name

import math as m
n = int(input('Enter any number :'))
result = m.factorial(n)
print(' Result :',result)

3rd method: Import only a single function

from math import factorial
n = int(input('Enter any number :'))
result = factorial(n)
print(' Result :',result)

4th Method: import single function

import math.factorial
n = int(input('Enter any number :'))
result = factorial(n)
print(' Result :',result)

Note : In the above cases 3 and 4, there is no need to write module name before function.

Python modules not only contains Python functions but also have some constants like pi and e. They are used a similar way as a function but without brackets.