Efficient List Subtraction

[Gordon McMillan]

Jonothan Farr wrote:

> I have also longed for built in support for the union and
> intersection of two sequences.
> 
> Perhaps:
> list.union(list2)
> and
> list.intersection(list2)

While not exactly what you're looking for, I suggest going to 
chordate.com and looking for kjbuckets. It's got sets and graphs; you 
can do intersections and closures...

- Gordon