On Wed, Sep 13, 2006 at 11:34:25AM -0400, Kent Johnson wrote:
>William O'Higgins Witteman wrote:
>> I have to walk a directory tree and examine files within it. I have a
>> set of directory names and filename patterns that I must skip while
>> doing this walk. How do I create a set of rules to skip files or
>> directory branches? I'm looking for something reasonably scalable,
>> 'cause I'm sure to need to update these rules in the future.
First, thanks to Kent and Dave for their thoughts - a big help and much
appreciated. Notes and results below, for archival posterity (so at
least *I'll* know where to look for it :-)
>def matchesAny(name, tests):
> for test in tests:
> if fnmatch.fnmatch(name, test):
> return True
> return False
fnmatch was a good choice for this in my case, because I have to do
case-insensitive matching of very simple patterns, but re or glob would
provide more power if needed. I originally put the return False inside
the conditional with else - but that meant that unless my name matched
on the last test in tests, it would always return False. Not what I
wanted. The above works very nicely without the return False line.
>for dirpath, dirnames, filenames in os.walk(baseDir):
> # Note use of slice assignment - you have to modify the caller's list
> dirnames[:] = [ name for name in dirnames if not matchesAny(name,
>dirsToSkip) ]
>
> filenames = [name for name in filenames if not matchesAny(name,
>filesToSkip) ]
>
> for name in filenames:
> # whatever file processing you want to do goes here
The above approach was not quite what I needed, because I had a list of
exclusion criteria and a list of inclusion criteria, but both could be
applied to the whole path. Therefore, I used this approach:
for dirpath, dirnames, filenames in os.walk(fs_path):
"""Filter the list of filenames to exclude elements in ToSkip"""
filenames[:] = [name for name in filenames if not
matches(os.path.join(dirpath,name),ToSkip)]
"""Filter the list of filenames to exclude elements not in ToKeep"""
filenames[:] = [name for name in filenames if
matches(os.path.join(dirpath,name),ToKeep)]
for fname in filenames:
# do what needs to be done
This is getting me just the results I was looking for, and I have to
say, I'm pretty pleased. Thanks again.
--
yours,
William
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