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Reverse Iteration in Python

Beginner

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Introduction

In Python, we can use a for loop to iterate over a list and execute a function for each element. However, what if we want to start from the last element and work our way backwards? In this challenge, you will need to create a function that executes the provided function once for each list element, starting from the list's last element.

Execute function for each list element in reverse

Write a function for_each_right(itr, fn) that takes a list itr and a function fn as arguments. The function should execute fn once for each element in itr, starting from the last one.

def for_each_right(itr, fn):
  for el in itr[::-1]:
    fn(el)
for_each_right([1, 2, 3], print) ## 3 2 1

Summary

In this challenge, you learned how to create a function that executes a provided function for each element in a list, starting from the last one. This can be useful when you need to process a list in reverse order.