scala 模式匹配

scala> val a = Array(1,2,3,4)
a: Array[Int] = Array(1, 2, 3, 4)


有繁入简，


scala> a.map(x => x match {
     |   case 0 => "zero"
     |   case 1 => "one"
     |   case 2 => "two"
     |   case _ => "other"
     | })
res2: Array[String] = Array(one, two, other, other)


scala> a.map(x => x match { case x => x })
res4: Array[Int] = Array(1, 2, 3, 4)



scala> a.map(case x => x)
<console>:1: error: illegal start of simple expression
a.map(case x => x)
      ^


scala> a.map{case x => x}
res3: Array[Int] = Array(1, 2, 3, 4)


scala> a.map{x => x}
res7: Array[Int] = Array(1, 2, 3, 4)