finding items that occur more than once in a list

[John Machin]

On Mar 22, 9:58 pm, Arnaud Delobelle <arno... at googlemail.com> wrote:
>
> Lastly, if one deals with a totally ordered set of object but they are
> not hashable (there isn't a good hash function), then Ninereeds' idea
> of sorting first is still useful.

... and if not totally ordered, then ... I'll just stand aside and cue
the timbot :-)

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52560