Sorting directory contents

[Peter Otten]

Wolfgang Draxinger wrote:

> I got, hmm not really a problem, more a question of elegance:
> 
> In a current project I have to read in some files in a given
> directory in chronological order, so that I can concatenate the
> contents in those files into a new one (it's XML and I have to
> concatenate some subelements, about 4 levels below the root
> element). It all works, but somehow I got the feeling, that my
> solution is not as elegant as it could be:
> 
> 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])
> 
> of course listdir and sorting could be done in a separate
> function, but I wonder if there was a more elegant approach.

If glob.glob() is good enough to replace your custom match_fname_pattern()
you can save a few steps:

pattern = os.path.join(sourcedir, "*.xml")
files = glob.glob(pattern)
files.sort(key=os.path.getmtime)
for fn in files:
    read_and_concatenate(fn)

Peter