Time a block of code with a context manager
Measure elapsed wall-clock time of a with-block using time.perf_counter.
- Python
- GreenSnippets
- MIT
- Executed with Python 3.11
import time
class Timer:
def __enter__(self):
self._start = time.perf_counter()
self.elapsed = None
return self
def __exit__(self, exc_type, exc, tb):
self.elapsed = time.perf_counter() - self._start
return False # never swallow exceptionsExample / expected output
with Timer() as t:
sum(range(1_000_000))
print(f"{t.elapsed:.3f}s")How it works
time.perf_counter() is the right clock for measuring durations: it is monotonic and high resolution. The result is stored on the object so it can be logged or asserted after the block, even if the block raised.
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