Python Function With Parameters, No Return

In the previous example, you have seen that python can take no parameter and return some value. In this example, you will learn that a function can take some parameter and output the results without returning the value.

Python Program To Reverse a String

In this example, we will accept a string as parameter and then reverse the string and print the output to the console. The function does not return anything.

## Program to reverse a string
my_string = "Great Country!"

# Function Definition
def reverse_string(s):
     for i in range(len(s)-1, -1, -1):
             print(s[i], end= " ")

# Function Call

There are a few things worth mentioning here. The function use the len() function which returns the length of the string. The len(s)-1 gives the index of the last character of the my_string.The index of first character is 0.

== RESTART: C:/Python_projects/Functions/ ==
! y r t n u o C   t a e r G 

Lets understand why range(len(s)-1, -1, -1) is going to work. The range function starts with len(s)-1 and goes up to -1. But it does not include -1 because range does not include the upper limit. Therefore, all characters starting with 12(because there are 13 characters in the string) to 0 are printed in reverse order.

Note that the last -1 in the range() function indicate that the function is decrementing.

In the next article, we will discuss about functions that do take parameters and also return a value.

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