On Wed, 28 Sep 2016 07:07 pm, Chris Angelico wrote: > On Wed, Sep 28, 2016 at 6:46 PM, Marko Rauhamaa <ma...@pacujo.net> wrote: >> Lawrence D’Oliveiro <lawrenced...@gmail.com>: >> >>> On Wednesday, September 28, 2016 at 6:51:17 PM UTC+13, ast wrote: >>>> I noticed that searching in a set is faster than searching in a list. >>> >>> That’s why we have sets. >> >> I would have thought the point of sets is to have set semantics, just >> like the point of lists is to have list semantics. > > And set semantics are what, exactly? Membership is a primary one.
Yep, that's pretty much it... > "Searching in a set" in the OP's language is a demonstration of the > 'in' operator, a membership/containment check. > > (Other equally important set semantics include intersection and union, Both of those revolve on membership testing. The union of A and B is the set of all elements in A plus those in B; the intersection of A and B is the set of all elements in both A and B. > but membership inclusion checks are definitely up there among primary > purposes of sets.) I can't think of a set operation (apart from add and remove) which doesn't resolve around membership. -- Steve “Cheer up,” they said, “things could be worse.” So I cheered up, and sure enough, things got worse. -- https://mail.python.org/mailman/listinfo/python-list
