pyperf Python performance guide (v0)pyperf rule ids (slugs)pyperf corpus targets pyperf evidence policy

pp-deepcopy-hot — measured, still hint pp-json-hot — measured, still hint pp-list-plus-rebind — xs = xs + [i] vs append pp-open-hot — measured, still hint pp-print-hot — print in loop vs join once (stdout discarded)pp-str-plus-hot — str += vs str.join

pp-datetime-format-in-loop pp-datetime-format-in-loop — removed 2026-10-23 (Asia/Shanghai)pp-deepcopy-in-loop — renamed 2026-10-27 (Asia/Shanghai)pp-json-in-loop — renamed 2026-10-27 (Asia/Shanghai)pp-open-in-loop — renamed 2026-10-27 (Asia/Shanghai)pp-print-in-loop — renamed 2026-10-27 (Asia/Shanghai)pp-regex-compile-in-loop — removed pp-regex-compile-in-loop — removed 2026-10-23 (Asia/Shanghai)pp-str-plus-in-loop — renamed 2026-10-27 (Asia/Shanghai)PP004 — removed PP004 — removed 2026-10-22 (Asia/Shanghai)

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pp-datetime-format-in-loop — removed 2026-10-23 (Asia/Shanghai)

Status: removed. strptime/strftime on a fixed string was about 172× only because the after side did not parse. A changing input has no compiled-format object to hoist, and the matcher cannot tell those cases apart.

Slug never reused.
No active matcher.

pp-datetime-format-in-loop

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