ex4.scala

object ex4 {

  object p1 {
    // 1
    val wishes = Map("iPad" -> 800, "iMac" -> 2000, "Telescope" -> 3000)
    val discounted = for ((k, v) <- wishes) yield (k, v * 0.9)
  }

  object p2 {
    // 2
    val words = new scala.collection.mutable.HashMap[String, Int]
    val in = new java.util.Scanner(new java.io.File("myfile.txt"))
    while (in.hasNext()) {
      val w = in.next()
      words(w) = words.getOrElse(w, 0) + 1
    }
    in.close()

    for ((k, v) <- words) printf("%s: %d\n", k, v)
  }

  import scala.collection.immutable._
  def scan(in:java.util.Scanner, m:Map[String, Int]):Map[String, Int] = {
    if (!in.hasNext()) m
    else {
      val key:String = in.next()
      scan(in, m + (key -> (m.getOrElse(key, 0) + 1)))
    }
  }
  
  // 3
  object p3 {
    
    val in = new java.util.Scanner(new java.io.File("myfile.txt"))
    val output = scan(in, new HashMap[String, Int])
    in.close()
    for ((k, v) <- output) printf("%s: %d\n", k, v)

  }

  object p4 {
    // 4
    val in = new java.util.Scanner(new java.io.File("myfile.txt"))
    val output = scan(in, new TreeMap[String, Int])
    in.close()
    for ((k, v) <- output) printf("%s: %d\n", k, v)
  }
  // 5


  object p6 {
    // 6
    val weeks = collection.mutable.LinkedHashMap("Monday" -> java.util.Calendar.MONDAY,
      "Tuesday" -> java.util.Calendar.TUESDAY,
      "Wednesday" -> java.util.Calendar.WEDNESDAY,
      "Thursday" -> java.util.Calendar.THURSDAY,
      "Friday" -> java.util.Calendar.FRIDAY,
      "Saturday" -> java.util.Calendar.SATURDAY,
      "Sunday" -> java.util.Calendar.SUNDAY)
    for ((k, v) <- weeks) printf("%s %d\n", k, v);
  }

  object p7 {
    // 7
    import scala.collection.JavaConversions.propertiesAsScalaMap
    val props: scala.collection.Map[String, String] = System.getProperties()
    val max_length = props.keys.maxBy(_.length).length
    for ((k, v) <- props) printf("%s | %s\n", (k + (" " * max_length)).substring(0, max_length), v)
  }

  object p8 {
    // 8
    def minmax(values: Array[Int]) = Array(values.min, values.max)

  }

  object p9 {
    // 9
    def lteggt(values: Array[Int], v: Int) = (values.count(_ < v), values.count(_ == v), values.count(_ > v))
  }

  object p10 {
    // 10
    "Hello".zip("World") // => (H, W), (e, o), (l, r), (l, l), (o, d)
                         // use case : ???
  }

}