In Scala, is there a way to take convert two lists into a Map?
dictionary, list, scala, scala-2.8, tuples
Solution
In 2.8 this is really simple using the `CanBuildFrom` functionality (as described by Daniel) and using `breakOut` with a type instruction to the compiler as to what the result type should be:
import scala.collection.breakOut
val m = (listA zip listB)(breakOut): Map[A,B]
The following would also work:
val n: Map[A,B] = (listA zip listB)(breakOut)
And (as EastSun, below, has pointed out) this has been added to the library as `toMap`
val o = (listA zip listB).toMap
As for reversing the map, you can do:
val r = m.map(_.swap)(breakOut): Map[B, A]
Problem
I have a two lists, a `List[A]` and a `List[B]`. What I want is a `Map[A,B]` but I want the semantics of `zip`. So started out like so: ``` var tuplesOfAB = listOfA zip listOfB ``` Now I'm not sure how to construct a `Map` from my `tuplesOfAB`. As a follow-up question, I also want to invert my map so that from a `Map[A,B]` I can create a `Map[B,A]`. Can anyone hit me with a clue-stick?