[Python-Dev] A wart which should have been repaired in 3.0?

[rdmurray at bitdance.com]

On Tue, 30 Dec 2008 at 21:30, rdmurray at bitdance.com wrote:
> On Tue, 30 Dec 2008 at 17:51, Phillip J. Eby wrote:
>>  At 02:32 PM 12/30/2008 -0800, Scott David Daniels wrote:
>> >  More trouble with the "just take the dirname":
>> > 
>> >       paths = ['/a/b/c', '/a/b/d', '/a/b']
>> >       os.path.dirname(os.path.commonprefix([
>> >                           os.path.normpath(p) for p in paths]))
>> > 
>> >  give '/a', not '/a/b'.
>>
>>  ...because that's the correct answer.
>
> But not the answer that is wanted.
>
> So the challenge now is to write a single expression that will yield
> '/a/b' when passed the above paths list, and also produce '/a/b' when
> passed the following paths list:
>
>    paths = ['/a/b/c', '/a/b/cd']

Sorry, now I see what you are saying: that in '/a/b' the 'b' is the
filename.  Clearly that wasn't what I intuitively expected our
notional 'commonpathprefix' command to produce, for whatever
that is worth :)

--RDM