Simple experiments with scala lists and maps.

scala_collections.scala

// define a simple list
scala> val l = List("a", "b", "c")
l: List[java.lang.String] = List(a, b, c)

// print each element of the list
scala> l.foreach{ println }
a
b
c

// same deal, with case syntax
scala> l.foreach{ case(x) => println(x) }
a
b
c

// in fact, you don't actually need the word case
scala> l.foreach{ (x) => println(x) }
a
b
c


// get a counter in the foreach loop
scala> l.zipWithIndex
res10: List[(java.lang.String, Int)] = List((a,0), (b,1), (c,2))

scala> l.zipWithIndex.foreach{ case(letter,i) => println(letter + " : " + i) }
a : 0
b : 1
c : 2

// now lets create a map of letter : index
// note that we use a var, since we want mutability
scala> var fieldToIndex: Map[String, Int] = Map()
fieldToIndex: Map[String,Int] = Map()

// we could add an individual item to the map:
fieldToIndex +=  ("asdf" -> 1)

//but instead, lets create our map using a loop:
l.zipWithIndex.foreach{ case(field, i) => fieldToIndex += (field -> i) }