Understanding the while-else Loop in Python

Photo by KOBU Agency on Unsplash

In Python, we often use while loops to repeatedly execute a block of code as long as a specified condition remains true. But did you know that Python allows you to pair an else statement with a while loop? The while-else combination can be useful in scenarios where you want to execute code after a loop completes, but only if the loop wasn’t interrupted by a break.

Let’s take a closer look at the while-else structure, how it works, and some scenarios where it can be particularly useful.

How the while-else Structure Works

A while-else structure is a while loop followed by an else block. Here’s the general form:

while condition:
    # Loop code
    if some_condition:
        break  # Exits the loop, so 'else' is skipped
else:
    # Executes only if the loop condition becomes False without hitting 'break'

The else block in a while-else loop only executes if the while loop finishes without encountering a break statement. If a break statement terminates the loop early, Python skips the else block entirely. This makes the else block useful for running additional code only when the loop completes "naturally."

Example 1: Searching for a Target Number in a List