[Python-ideas] find-like functionality in pathlib

[Guido van Rossum]

On Mon, Jan 11, 2016 at 10:57 AM, Gregory P. Smith <greg at krypto.org> wrote:

> On Wed, Jan 6, 2016 at 3:05 PM Brendan Moloney <moloney at ohsu.edu> wrote:
>
>> Its important to keep in mind the main benefit of scandir is you don't
>> have to do ANY stat call in many cases, because the directory listing
>> provides some subset of this info. On Linux you can at least tell if a path
>> is a file or directory.  On windows there is much more info provided by the
>> directory listing. Avoiding subsequent stat calls is also nice, but not
>> nearly as important due to OS level caching.
>>
>
> +1 - this was one of the two primary motivations behind scandir.  Anything
> trying to reimplement a filesystem tree walker without using scandir is
> going to have sub-standard performance.
>
> If we ever offer anything with "find like functionality" related to
> pathlib, it *needs* to be based on scandir.  Anything else would just be
> repeating the convenient but untrue limiting assumptions of os.listdir:
> That the contents of a directory can be loaded into memory and that we
> don't mind re-querying the OS for stat information that it already gave us
> but we threw away as part of reading the directory.
>

And we already have this in the form of pathlib's [r]glob() methods.
There's a patch to the glob module in http://bugs.python.org/issue25596 and
as soon as that's committed I hope that its author(s) will work on doing a
similar patch for pathlib's [r]glob (tracking this in
http://bugs.python.org/issue26032).

-- 
--Guido van Rossum (python.org/~guido)
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