What for -- for? (was A bug?)

Rustom Mody rustompmody at gmail.com
Wed Oct 29 06:15:13 CET 2014


On Wednesday, October 29, 2014 10:29:48 AM UTC+5:30, Zachary Ware wrote:
> On Tue, Oct 28, 2014 at 11:40 PM, Rustom Mody  wrote:
> > On Wednesday, October 29, 2014 9:53:46 AM UTC+5:30, Zachary Ware wrote:
> >> On Tue, Oct 28, 2014 at 11:16 PM, Zachary Ware wrote:
> >> > def get_abc_map(cls):
> >> >    return {n: issubclass(cls, getattr(abc, n)) for n in dir(abc) if
> >> > n[0].isupper()}
> >>
> >> Of course, Gmail decided to wrap my long line for me.  In case it's
> >> not obvious, that should be a single line.
> >
> > Thanks
> >
> > Wrapping -- no problem.
> > But the isupper looks like black-magic :-)
> >
> > And removing the ' ... if n[0].isupper()'
> > breaks the code
> 
> It's a terrible hack for 2/3 compatibility; in 3 I'd do "if not
> n.startswith('__')" since the Python 3 collections.abc module only
> contains ABCs (and the standard dunder names).  Python 2 has all the
> ABCs mixed into the toplevel collections namespace with some other
> non-ABCs, but it happens that all the ABCs are capitalized, while the
> non-ABCs are not.  The ABCs are imported into collections from
> _abcoll, but _abcoll also some uncapitalized non-ABCs as well.
> 
> For somewhat greyer magic, do 'from abc import ABCMeta' and filter the
> collections<.abc> namespace with isinstance(obj, ABCMeta).  I just
> used the above because it's short and sweet and keeps the name handy
> :)

Ha!
Thanks

Maybe nicer to filter out the false's with a filter-false thus??

def ff(d): return [n for n in d if d[n]]



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