basic scala map features

worldcups.scala

object MapTests extends Application {
  override def main(args: Array[String]) {
    //reference http://www.scala-lang.org/api/current/scala/collection/immutable/Map.html
    val worldCupWinners = Map(1975 -> "West Indies",
      1979 -> "West Indies",
      1983 -> "India",
      1987 -> "Australia",
      1992 -> "Pakistan",
      1996 -> "Sri Lanka",
      1999 -> "Australia",
      2003 -> "Australia",
      2007 -> "Australia")
    val evenYears = worldCupWinners filterKeys (_ % 2 == 0)
    println("evenYears: " + evenYears)

    val ausTotalWins = worldCupWinners.filter {
      element =>
        val (year, country) = element
        country contains "Aus"
    }
    println("ausTotalWins: " + ausTotalWins)

    val countAfter2k = ausTotalWins.filterKeys(_ >= 2000).size
    val countBefore2k = ausTotalWins.filterKeys(_ < 2000).size
    println("countAfter2k:" + countAfter2k)
    println("countBefore2k:" + countBefore2k)
    // some and none goodies
    println(worldCupWinners.get(1983))
    println(worldCupWinners.get(2000))

    //scala map is immutable so need to use update for 2011 winner as below
    worldCupWinners.updated(2011, "Winner of India vs Pakistan")
    // its immutable so it wont add the new value
    println(worldCupWinners.mkString(", "))
    // another try
    val updWorldCupWinners = worldCupWinners.updated(2011, "Winner of India vs Pakistan")
    println(updWorldCupWinners.mkString(", "))

    //head vs tail
    println("head :" + worldCupWinners.head)
    println("tail :" + worldCupWinners.tail)

  }
}