On Thu, Jul 23, 2009 at 7:28 AM, Andy Kish<agkish@gmail.com> wrote:
Hi all,
I think the addition of a universal set object would be a nice touch for python sets. Manipulation of collections of sets becomes much easier with it. [...]
What would set.universal() - {1, 2, 3} return? Would this be a ValueError, or would you want to also implement all cofinite sets? How would 'for x in set.universal()' behave? What's len(set.universal())? It seems to me that set.universal() can't be a full-fledged Python set, so it would have to be something else. And then x = set.universal().intersection(*sets) will sometimes be returning a true set (i.e., when sets is nonempty), and sometimes the reduced-functionality set.universal(). In many cases you're still going to need to distinguish before doing anything with x. Not-all-binary-operations-have-to-have-an-identity-ly yours, -- Mark