Cartesian product of two lists

Question

Given a map where a digit is associated to several characters

scala> val conversion = Map(\"0\" -> List(\"A\", \"B\"), \"1\" -> List(\"C\", \"D\"))
         


        

Answer 1

I just did that as follows and it works

    def cross(a:IndexedSeq[Tree], b:IndexedSeq[Tree]) = {
        a.map (p => b.map( o => (p,o))).flatten
    }

Don't see the $Tree type that am dealing it works for arbitrary collections too..