On Tue, Dec 22, 2015 at 4:23 PM, Guido van Rossum <guido@python.org> wrote:

The two-level iteration forced upon you by os.walk() is indeed often unnecessary -- but handling dirs and files separately usually makes sense,

indeed, but not always, so a simple API that allows you to get a flat walk would be nice....

Of course for that basic use case, you could just write your own wrapper around os.walk:

sure, but having to write "little" wrappers for common needs is unfortunate...

The problem isn't designing a nice walk API; it's integrating it with pathlib.*

indeed -- I'd really like to see a *walk in pathlib itself. I've been trying to use pathlib whenever I need, well, a path, but then I find I almost immediately need to step out and use an os.path function, and have to string-fy it anyway -- makes me wonder what the point is..

 And honestly, if open, os.walk, etc. aren't going to work with Path objects, 

but they should -- of course they should..... 

Truly pushing for adoption of a new abstraction like this takes many years -- pathlib was new (and provisional) in 3.4 so it really hasn't been long enough to give up on it. The OP hasn't!

it will take many years for sure -- but the standard library cold at least adopt it as much as possible.

Path.walk would be a nice start :-)

My example: one of our sysadmins wanted a little script to go thorugh an entire drive (Windows), and check if any paths were longer than 256 characters (Windows, remember..)

I came up with this:

def get_all_paths(start_dir='/'):

    for dirpath, dirnames, filenames in os.walk(start_dir):

        for filename in filenames:

            yield os.path.join(dirpath, filename)

too_long = []

for p in get_all_paths('/'):

    print("checking:", p)

    if len(p) > 255:

        too_long.append(p)

        print("Path too long!")

way too wordy! 

I started with pathlib, but that just made it worse.

now that I think about it, maybe I could have simpily used pathlib.Path.rglob....

However, when I try that, I get a permission error:

/Users/chris.barker/miniconda2/envs/py3/lib/python3.5/pathlib.py in wrapped(pathobj, *args)

    369         @functools.wraps(strfunc)
    370         def wrapped(pathobj, *args):
--> 371             return strfunc(str(pathobj), *args)
    372         return staticmethod(wrapped)
    373

PermissionError: [Errno 13] Permission denied: '/Users/.chris.barker.xahome/caches/opendirectory'

as the error comes insider the rglob() generator, I'm not sure how to tell it to ignore and move on....

os.walk is somehow able to deal with this.

-CHB

--

Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chris.Barker@noaa.gov