ID : 454

viewed : 150

Tags : PythonPython Loop

91

The `range()`

function in the `for`

loop can also be used to iterate backward by just setting the third parameter to -1 in Python. In this tutorial, we discuss this function further so that you can execute this program too.

`range()`

Function in PythonThe traditional use of the `range()`

function with `for`

loop is demonstrated in the following coding example:

`for x in range(0, 10): print(x) `

Output:

`0 1 2 3 4 5 6 7 8 9 `

This usage of the `range()`

function gives us values that start with 0 and end with 9 with increments of 1 each time. But what if we want to start with 10 and end with 1 with decrements of 1 each time. Luckily for us, the `range()`

function already has a solution to this problem.

The `range()`

function has a third parameter determining the iterative change in the first value until it reaches the second value. This third parameter is known as a step. We can specify -1 in the step parameter if we want to decrement the first parameter by 1 in each iteration. You can use the following program snippet to iterate backward using the step parameter in the `range()`

function:

`for x in range(10, 0, -1): print(x) `

Output:

`10 9 8 7 6 5 4 3 2 1 `

We iterated through 10 to 1 while decrementing by 1 each time with the `range()`

function in the code above. This approach is so easy to use and straightforward that there is no need for another approach to achieve this goal.