How Can I Exit Nested Loops Gracefully in Python?

Breaking Out of Nested Loops: A Cleaner Solution

While throwing an exception can provide a way to exit nested loops prematurely, it is not always the most desirable approach. Fortunately, Python offers alternative methods for achieving this without resorting to exceptions.

One elegant solution involves utilizing the break and continue keywords:

<code class="python">for x in range(10):
    for y in range(10):
        print(x * y)
        if x * y > 50:
            break
    else:
        continue  # only executed if the inner loop did NOT break
    break  # only executed if the inner loop DID break</code>

The break statement immediately exits the innermost loop, while the continue statement proceeds to the next iteration of the outer loop. This allows for precise control over loop termination based on specific conditions.

This approach can be extended to deeper nested loops as well:

<code class="python">for x in range(10):
    for y in range(10):
        for z in range(10):
            print(x, y, z)
            if (x * y * z) == 30:
                break
        else:
            continue
        break
    else:
        continue
    break</code>

In this code, the loops are terminated when the condition (x * y * z) == 30 is met. By carefully combining break and continue statements, you can create complex control flow within multiple levels of loops. This provides a cleaner and more maintainable way to exit nested loops when necessary.

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