[Python-Dev] Updates to PEP 471, the os.scandir() proposal

[Ben Hoyt]

> On a system which did not supply is_dir automatically I would write that as:
>
>   for entry in os.scandir(path):  # info defaults to 'os', which is
> basically None in this case
>       if ignore_entry(entry.name):
>           continue
>       if os.path.isdir(entry.full_name):
>           # do something interesting
>
> Not hard to read or understand, no time wasted in unnecessary lstat calls.

No, but how do you know whether you're on "a system which did not
supply is_dir automatically"? The above is not cross-platform, or at
least, not efficient cross-platform, which defeats the whole point of
scandir -- the above is no better than listdir().

-Ben