break — Advanced Examples

Exits the nearest enclosing for or while loop immediately

EasyIntermediateAdvancedExpert

Break in complex iteration patterns

Using break with itertools and generators.

python
import itertools

# Break with itertools.count (infinite iterator)
for i in itertools.count(1):
    if i * i > 100:
        print(f"First square > 100: {i}^2 = {i*i}")
        break

# Using break to implement takewhile manually
def take_until(predicate, iterable):
    result = []
    for item in iterable:
        if predicate(item):
            break
        result.append(item)
    return result

data = [2, 4, 6, 7, 8, 10]
evens = take_until(lambda x: x % 2 != 0, data)
print(f"Evens before first odd: {evens}")

# Break with walrus operator
nums = iter([3, 1, 4, 1, 5, 0, 2, 6])
while (n := next(nums, None)) is not None:
    if n == 0:
        print("Hit zero, stopping")
        break
    print(n, end=" ")
print()
Expected Output
First square > 100: 11^2 = 121
Evens before first odd: [2, 4, 6]
3 1 4 1 5 
Hit zero, stopping

break works with any loop, including those over infinite iterators. Combined with walrus operator, it enables clean sentinel-based loops.

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