GH-119169: Slightly speed up os.walk(topdown=True) - #121431
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encukou merged 3 commits intoSep 3, 2025
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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.
eendebakpt
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Apr 17, 2025
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Lib/os.py
| # above. | ||
| if followlinks or not islink(new_path): | ||
| stack.append(new_path) | ||
| if dirs: |
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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.
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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, call os.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())