How to Escape Nested Loops in Python Without Exceptions?

Escaping Nested Loops without Exceptions

While using exceptions to break out of nested loops is possible, it can be cumbersome. Fortunately, there are cleaner approaches available in Python.

Using the "break" and "continue" Statements

A more elegant solution involves using the break and continue statements. The break statement immediately exits the innermost loop, while continue continues to the next iteration within the current loop.

Consider the following nested loop:

<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>

In this example, the break statement within the inner loop allows us to exit both loops when the condition x * y > 50 is met. The else clause after the inner loop checks if the inner loop terminated normally (without encountering a break). If so, it executes the continue statement to proceed to the next iteration of the outer loop.

Example with Multiple Nested Loops

This technique can be extended to deeper 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>

This code demonstrates how to break out of all three nested loops when the condition (x * y * z) == 30 is satisfied. The else and continue statements ensure that the outer loops are traversed correctly based on the termination status of the inner loops.

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