Getting all the *files* from a directory -- A better way??

Ken Seehof kens at sightreader.com
Wed Mar 28 02:45:31 CEST 2001


----- Original Message -----
From: "Paul Jackson" <pj at sgi.com>
Newsgroups: comp.lang.python
To: <python-list at python.org>
Sent: Tuesday, March 27, 2001 3:15 PM
Subject: Re: Getting all the *files* from a directory -- A better way??


> Quentin Crain asks:
> |> Here is how I get all the files from a directory:
> |>
> |>   dir="a/b/c"
> |>   files=filter(os.path.isfile,["%s/%s"%(dir,f) for f in os.listdir
> |> (dir)])
> |>
> |> Is this *REALLY* the Pythonic way to do this? (OR, why does
> |> os.listdir return only file names, and not the path given
> |> prepended?)
>
> Close - better to use os.path.join (more portable across
> operating environments with different path component
> separator characters, such as '\' in DOS/Windows).

Actually '/' is generally portable.  I use os.path.join for combining
variables, but I use '/' within hard-coded relative paths.

e.g.:
f = os.path.join(root, 'doc/chapter2/spam.html')
rather than
f = os.path.join(root, os.path.join('doc', os.path.join('chapter2',
'spam.html'))))

This is fine because open() and all other file functions automagically
normalize the path to the operating system.  Warning: if you want
to use the result in a command line (e.g. os.popen()) be sure to
normalize the path with os.path.normpath().

> Try:
>
>     dir="a/b/c"
>     files = filter(
> os.path.isfile,
> [os.path.join(dir, f) for f in os.listdir(dir)]
>     )
>
> I'd say that the os.listdir() method only returns the
> directory entries (by simple basename), not with any
> path prefixed, because it is intended to be basic
> operation on a directory, and directories have just
> the simple name entries, not full pathnames, in them.
>
> What one wants to do with those directory entries, after
> extracting them with os.listdir(), can vary all over the
> lot, and may or may not involve joining the directory path.
> So that should be left up to the caller of listdir().
>
> --
>                           I won't rest till it's the best ...
>                           Manager, Linux System Software
>                           Paul Jackson <pj at sgi.com> 1.650.933.1373
> --
> http://mail.python.org/mailman/listinfo/python-list
>





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