On May 4, 5:04 pm, Paul McGuire <p... at austin.rr.com> wrote: > Does set membership test for equality ("==") or identity ("is")? I > just did some simple class tests, and it looks like sets test for > identity. Sets are like dictionaries, they test for equality: >>> a=1,2 >>> b=1,2 >>> a is b False >>> a in set([b]) True -- Arnaud