By default, Scala uses the immutable Map

object Demo
{
  def main(args : Array[String])
  {
    var a : Map[String, Int] = Map();
    var b  = Map("Hannah" -> 12, "Hadley" -> 1);

    // add pairs
    a = a + ("Lin" -> 39, "Yanhua" -> 38)

    println(a.keys); // keys
    println(a.values); // values

    // concatenate
    var c = a ++ b
    println(c)

    println(a("Lin")); // access element

    // foreach
    a.foreach(t => println(t._1+" "+t._2))

    // contains
    println(a.contains("Lin"))

    // remove pair
    a = a - "Lin"
    println(a)
  }
}
		

import scala.collection.mutable.Map
object Demo
{
  def main(args : Array[String])
  {
    var a : Map[String, Int] = Map("Lin" -> 39, "Yanhua" -> 38)

    a("Lin") = 40
    println(a);
  }
}
		

Alvin Alexander

Map Immutable

Map Mutable