Mapの操作。
$ scala Welcome to Scala version 2.9.2 (OpenJDK 64-Bit Server VM, Java 1.7.0_55). Type in expressions to have them evaluated. Type :help for more information. scala> Map(1 -> "a", 2 -> "b", 3 -> "c") get (1) res0: Option[java.lang.String] = Some(a) scala> Map(1 -> "a", 2 -> "b", 3 -> "c") get (1) res1: Option[java.lang.String] = Some(a) scala> Map(1 -> "a", 2 -> "b", 3 -> "c") (1) res2: java.lang.String = a scala> Map(1 -> "a", 2 -> "b", 3 -> "c") getOrElse (1, "d") res3: java.lang.String = a scala> Map(1 -> "a", 2 -> "b", 3 -> "c") getOrElse (4, "d") res4: java.lang.String = d scala> Map(1 -> "a", 2 -> "b", 3 -> "c") isDefineAt (1) <console>:8: error: value isDefineAt is not a member of scala.collection.immutable.Map[Int,java.lang.String] Map(1 -> "a", 2 -> "b", 3 -> "c") isDefineAt (1) ^ scala> Map(1 -> "a", 2 -> "b", 3 -> "c") isDefinedAt (1) res6: Boolean = true scala> Map(1 -> "a", 2 -> "b", 3 -> "c") isDefinedAt (4) res7: Boolean = false