chapter 16

Author: tobyweston

src/main/scala/s4j/scala/chapter16/ArrayExample.scala

@@ -0,0 +1,21 @@
+package s4j.scala.chapter16
+
+object ArrayExample extends App {
+
+  val numerals = Array("I", "II", "III", "IV", "V", "VI", "VII")
+
+  println(numerals(5))
+
+  for (i <- 0 to numerals.length - 1)
+    println(i + " = " + numerals(i))
+
+  // could have written this
+  for (i <- 0 to numerals.length - 1)
+    println(i + " = " + numerals.apply(i))
+
+  // more functional version
+  for ((value, index) <- numerals.zipWithIndex)
+    println(index + " : " + value)
+
+  numerals(1) = "?"
+}

src/main/scala/s4j/scala/chapter16/Directory.scala

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+package s4j.scala.chapter16
+
+class Directory {
+  private val numbers = scala.collection.mutable.Map(
+    "Athos" -> "7781 456782",
+    "Aramis" -> "7781 823422",
+    "Porthos" -> "1471 342383",
+    "D`Artagnan" -> "7715 632982"
+  )
+
+  def apply(name: String) = {
+    numbers.get(name)
+  }
+
+  def update(name: String, number: String) = {
+    numbers.update(name, number)
+  }
+
+  def update(areaCode: Int, newAreaCode: String) = {
+    numbers.foreach(entry => {
+      if (entry._2.startsWith(areaCode.toString))
+        numbers(entry._1) = entry._2.replace(areaCode.toString, newAreaCode)
+    })
+  }
+
+  def update(areaCode: Int, anotherArgument: String, newAreaCode: String) = ???
+
+  override def toString = numbers.toString()
+}
+
+object Directory extends App {
+
+  val yellowPages = new Directory()
+  println(yellowPages)
+  yellowPages(7781) = "7555"
+  yellowPages(7998, "another argument") = "???"
+  println(yellowPages)
+
+}