Speed up counting in statistics.fmean() by rhettinger · Pull Request #148875 · python/cpython

rhettinger · 2026-04-22T14:42:43Z

Implement a faster counting strategy that avoids tuple creation, indexing, and destruction.

Baseline timing:

% ./python.exe -m timeit -s 'from statistics import fmean' 'fmean(iter(range(10**3)))'
20000 loops, best of 5: 18.7 usec per loop

After the PR:

% ./python.exe -m timeit -s 'from statistics import fmean' 'fmean(iter(range(10**3)))'
20000 loops, best of 5: 11.4 usec per loop

Co-authored-by: Shrey Naithani <shrey.naithani@shelllite.tech>

Speed up counting in fmean()

6303c76

rhettinger added performance Performance or resource usage skip issue skip news labels Apr 22, 2026

bedevere-app Bot added the awaiting core review label Apr 22, 2026

Shrey-N reviewed Apr 22, 2026

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Comment thread Lib/statistics.py Outdated

Update Lib/statistics.py

0416f7d

Co-authored-by: Shrey Naithani <shrey.naithani@shelllite.tech>

rhettinger merged commit fbc7676 into python:main Apr 23, 2026
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bedevere-app Bot removed the awaiting core review label Apr 23, 2026

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