Range Backwards in Python

Muhammad Waiz Khan Jan 03, 2023 Jan 31, 2021 Python Python Range
  1. Range Backwards in Python Using the range() Function
  2. Range Backwards in Python Using the reversed() Function
  3. Range Backward in Python Using Extra Variable
Range Backwards in Python

This tutorial will explain multiple ways to range or loop backward in Python. Backward range means starting the loop from the largest index and iterating backward till the smallest index.

Range Backwards in Python Using the range() Function

To range backward, we can use the range() method and pass starting index like 100 as the first argument, stopping index like -1 (as we want to iterate till 0) as the second argument, and step size of -1 as the iteration is backward.

Note
This method is useful if we want to iterate backward between some specific range or index like 100 to 50.

The example code to implement backward loop is below:

for i in range(100,-1,-1):
    #do something

Range Backwards in Python Using the reversed() Function

Another way to range backward in Python is to use the reversed() function that takes the range() as the input. The example code below demonstrates how to implement a backward loop using the reversed() function.

for i in reversed(range(100)):
    #do something

The above code will start from 99 and iterate till 0.

Range Backward in Python Using Extra Variable

A simple approach is to initialize another variable and subtract it with the range() variable to loop backward.

Example code:

for x in range(100):
    i = 100 - x
    #do something