How to create all possible combinations from the elements of a list?

Question

I have the following list:

List(a, b, c, d, e)

How to create all possible combinations from the above list?

I expect something like:

Answer 1

def powerset[A](s: Set[A]) = s.foldLeft(Set(Set.empty[A])) { case (ss, el) => ss ++ ss.map(_ + el) }

Sounds like you need the Power set.