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gh-143658: Usestr.lower andreplace to further improve performance ofimportlib.metadata.Prepared.normalized#144083
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….metadata.Prepared.normalizedCo-authored-by: Henry Schreiner <henryschreineriii@gmail.com>
str.lower andreplace to further improve performance ofimportlib.metadata.Prepared.normalizedstr.lower andreplace to further improve performance ofimportlib.metadata.Prepared.normalizedhauntsaninja approved these changesJan 20, 2026
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hugovk commentedJan 22, 2026
Attached code for benchmarking and making the chart, and the results data from my macOS machine: And charts and data of benchmarking on macOS, Ubuntu and Windows via GitHub Actions:    |
sergey-miryanov approved these changesJan 23, 2026
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LGTM
brettcannon approved these changesJan 23, 2026
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Follow on from#143660 which replaced
re.subwithstr.translate.@henryiii discovered that whilst that is an improvement on Python 3.10-3.11 and 3.14, the performance of
str.translateis much worse on Python 3.12 and 3.13, and can be worse than the originalre.sub.Further, his fix inpypa/packaging#1064 to replace
str.translatewithstr.lowerandstr.replacecalls is better than both the other options across all Python versions, to varying degrees.I benchmarked all three across all available Python Build Standalone versions from 3.10-3.15 on macOS:
I also benchmarked Windows and Ubuntu it's the same pattern.
Whilst the improvement isn't as large for CPython 3.15 as it is for libraries such as
packagingthat support a wide range of Pythons,importlib.metadatadoes have a backport, and I'll updatepython/importlib_metadata#529 once this is merged.str.translateto improve performance ofimportlib.metadata.Prepared.normalized#143658