Sorting directory contents

[Paul Rubin]

Wolfgang Draxinger <wdraxinger at darkstargames.de> writes:
> src_file_paths = dict()
> for fname in os.listdir(sourcedir):
>         fpath = sourcedir+os.sep+fname
>         if not match_fname_pattern(fname): continue
>         src_file_paths[os.stat(fpath).st_mtime] = fpath
> for ftime in src_file_paths.keys().sort():
>         read_and_concatenate(src_file_paths[ftime])

Note you have to used sorted() and not .sort() to get back a value
that you can iterate through.

Untested:

  from itertools import ifilter

  goodfiles = ifilter(match_fname_pattern,
                      (sourcedir+os.sep+fname for \
                         fname in os.listdir(sourcedir))

  for f,t in sorted((fname,os.stat(f).st_mtime) for fname in goodfiles,
                    key=lambda (fname,ftime): ftime):
     read_and_concatenate(f)

If you're a lambda-phobe you can use operator.itemgetter(1) instead of
the lambda.  Obviously you don't need the separate goodfiles variable
but things get a bit deeply nested without it.