GH-119169: Slightly speed up os.walk(topdown=True)
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When `os.walk()` traverses into subdirectories in top-down mode, call `os.path.join()` once to add a trailing slash, and use string concatenation thereafter to generate child paths.
barneygale
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os.walk(topdown=True)os.walk(topdown=True)
eendebakpt
reviewed
Apr 17, 2025
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How much of the gain is due to the elimination of os.join and how much due to the check on empty dirs? On my system a walk of a folder with github repositories (including the cpython repo) has dirs empty about 60% of the times.
lkollar
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Sep 9, 2025
…121431) pythonGH-119186: Slightly speed up `os.walk(topdown=True)` When `os.walk()` traverses into subdirectories in top-down mode, call `os.path.join()` once to add a trailing slash, and use string concatenation thereafter to generate child paths.
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When
os.walk()traverses into subdirectories in top-down mode, callos.path.join()once to add a trailing slash, and use string concatenation thereafter to generate child paths.(this trick is already used in
os.fwalk())os.walk()#119169