Level 6Exercise #146

Time a code block

Create a context manager that prints elapsed seconds after the wrapped block, even if it raises.

What you’ll practice

This Level 6 exercise focuses on contextmanager in the Professional curriculum. Solve the challenge prompt above using clear, idiomatic Python and the relevant language or standard-library tools.

Relevant Python reference: contextlib — Context management.

Sample Test Cases

Example #1

Input:(lambda: [t := timer('build'), t.__enter__(), t.__exit__(None, None, None)][0] and 'ok')()

Output:prints elapsed time

Reference Solution

Reveal Reference Solution

def timer(label: str):
    from contextlib import contextmanager
    from time import perf_counter
    @contextmanager
    def _timer():
        start = perf_counter()
        try:
            yield
        finally:
            print(f'{label}: {perf_counter()-start:.3f}s')
    return _timer()

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Time a code block

What you’ll practice

Sample Test Cases

Further Reading

Reference Solution