[Patches] [ python-Patches-786237 ] os.path.exists should use os.access when possible

Sun Aug 31 10:55:12 EDT 2003

Patches item #786237, was opened at 2003-08-10 15:03
Message generated for change (Comment added) made by loewis
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Category: Library (Lib)
Group: None
>Status: Closed
>Resolution: Rejected
Priority: 5
Submitted By: Matthew Mueller (donut)
Assigned to: Nobody/Anonymous (nobody)
Summary: os.path.exists should use os.access when possible

Initial Comment:
Compared to os.access, os.stat is very slow (probably
due constructing to the stat object it returns).  

Therefore, os.path.exists should use os.access instead,
when possible.  (posixpath, I guess ntpath too.) 
(I didn't include a patch for ntpath since I can't test
it.)

As a bonus, the code is cleaner too. :)

examples:
> touch file_that_exists

> python2.3 timeit.py -s "from os.path import exists"
"exists('file_that_exists')"                          

100000 loops, best of 3: 15.6 usec per loop

> python2.3 timeit.py -s "from newposixpath import
exists" "exists('file_that_exists')"                  

100000 loops, best of 3: 6.17 usec per loop

> python2.3 timeit.py -s "from os.path import exists"
"exists('file_that_does_not_exist')"                  

10000 loops, best of 3: 48.9 usec per loop

> python2.3 timeit.py -s "from newposixpath import
exists" "exists('file_that_does_not_exist')"
100000 loops, best of 3: 6.37 usec per loop

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>Comment By: Martin v. Löwis (loewis)
Date: 2003-08-31 18:55

Message:
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This patch is incorrect (rejecting it), see

http://mail.python.org/pipermail/python-dev/2002-June/025511.html

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