Standard ways to get union, intersection, difference of lists?

[Paul Rudin]

>>>>> "Mickel" == Mickel Grönroos <mickel at csc.fi> writes:

    > Hi!  Are there any standard list methods for getting the
    > intersection and difference of two lists? (The union is easy
    > ("list1.extend(list2)"), unless you want it to contain unique
    > values.)

[snip]

    > I realize I could quite easily implement this myself, but I was
    > hoping for a built-in solution.

You might want to take a look at the sets module in Python 2.3. It's
not exactly what you ask for since sets.Sets are not lists - but they
do support these operations and can easily be converted to or from
lists.