break — Intermediate Examples

Exits the nearest enclosing for or while loop immediately

EasyIntermediateAdvancedExpert

Break with for/else

Using else to detect if break was triggered.

python
# Search with else
def find_prime_factor(n):
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            return i
    return n  # n is prime

# for/else: else runs only if loop completes without break
numbers = [15, 7, 20, 11]
for n in numbers:
    for i in range(2, n):
        if n % i == 0:
            print(f"{n} is composite (divisible by {i})")
            break
    else:
        print(f"{n} is prime")
Expected Output
15 is composite (divisible by 3)
7 is prime
20 is composite (divisible by 2)
11 is prime

The else clause of a for loop runs only when the loop finishes without hitting break. This is a clean search pattern.

Break in nested loops

Break only exits the innermost loop.

python
# Break only exits ONE level
matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
target = 5
found = False
for i, row in enumerate(matrix):
    for j, val in enumerate(row):
        if val == target:
            print(f"Found {target} at ({i}, {j})")
            found = True
            break
    if found:
        break

# Cleaner: use a function to break all levels
def find_in_matrix(matrix, target):
    for i, row in enumerate(matrix):
        for j, val in enumerate(row):
            if val == target:
                return (i, j)
    return None

print(find_in_matrix(matrix, 8))
Expected Output
Found 5 at (1, 1)
(2, 1)

break only exits the innermost loop. For nested loops, use a flag variable or wrap the search in a function and use return instead.

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