Py2.3: Feedback on Sets (fwd)

[Raymond Hettinger]

[Raymond]
> > * Is there a compelling need for additional set methods like
> >    Set.powerset() and Set.isdisjoint(s) or are the current
> >    offerings sufficient?

[David Mertz]
> I confess that I have not used sets for anything beyond testing.  I love
> the concept, but I just haven't had the need yet (especially in
> something where I want to require 2.3).
>
> The mention of Set.powerset() above is quite interesting to me.  It
> feels both exciting and dangerous :-).


There would need to be compelling use cases before it would be
added to the API.

How about just adding a cut-and-paste recipe to the docs:

from sets import Set
def powerset(iterable):
    data = list(iterable)
    for i in xrange(2**len(data)):
        yield Set([e for j,e in enumerate(data) if i&(1<<j)])

>>> list(powerset('abc'))
[Set([]), Set(['a']), Set(['b']), Set(['a', 'b']), Set(['c']), Set(['a', 'c']),
Set(['c', 'b']), Set(['a', 'c', 'b'])]


Raymond Hettinger