Lesson 2: Functions and Modules

Functions

Block of organized, reusable code that is used to perform a single, related action
Provide better modularity for your application and a high degree of code reusing
Python gives you many built-in functions like print(), len() etc..
It is also possible to define user-defined functions
Global vs. local variables

Write a small function that checks if the number entered by the user is 5



In [1]:

    
# FUNCTION DEFINITION
def check_if_5(user_number):
    """This function just checks if the number passed to it is equal
    to 5. It returns 1 if the number is 5 and returns 0 if the number is not 5 """
    if user_number == 5:
        return 1
    else:
        return 0

#FUNCTION CALL
return_val = check_if_5(5)

if return_val == 1:
    print("It is 5")
else:
    print("It is not 5")









    



It is 5

Modules

A set of related functions can be grouped together as module
A module is nothing but a python file
The open source community continuosly builds modules and makes it available for us
To access these modules we need to use the "import command"

Let us import a commonly used module and access one of its functions.



In [2]:

    
import random
print('A random number between 1 and 6 is: ',random.randint(1,6))









    



A random number between 1 and 6 is:  6

It is also possible to import specific functions from within the module directly. When you do this make sure you have not used the same name for your function.



In [3]:

    
from random import randint
print('A random number between 1 and 6 is: ',randint(1,6))









    



A random number between 1 and 6 is:  3