Scala 入门笔记 - 模式匹配

    name match {
      case "aaa" => println("this is aaa")
      case "bbb" => println("this is bbb")
      case _ => println("lala")

    }


// 匹配类型
case str: String => ....
case int: Int => ....
case matchType: MatchType => .... // 匹配自定义类型

  // 自定义类型
  class MatchType {
  }// 匹配数组、元组， 集合

val arr = Array(1, 2, 3, 6)arr match {  case Array(3, a, b, c) => println(s"case: $a, $b, $c")  case Array(_, x, y, z) => println(s"case: $x, $y, $z")  case _ => println("no matched")}

val tup = ("a", 1, 4)tup match {  case ("c", b, 4) => println(s"case:  $b")  case ("a", x, y) => println(s"case: $x, $y")  case _ => println("no matched")}

val list1 = List(0, 1, 2, 3)list1 match {    // Nil 是个空List, :: 从右向左运算 (0 :: Nil 生成一个List(0))  case 0 :: Nil => println("case1: 0")  case 2 :: a :: b :: c :: d :: Nil => println(s"case2: $a, $b, $c, $d")  case 0 :: a => println(s"case3: $a")  case List(0, a, b, c) => println(s"case4: $a, $b, $c")  case _ => println("hahaha")}// 匹配样例类

object CaseClassDemo {  def main(args: Array[String]): Unit = {    val arr = Array(CheckTimeOutTask, SubmitTask("1000", "task-0001"), HeartBeat(3000))    arr(Random.nextInt(arr.length)) match {      case CheckTimeOutTask => println("CheckTimeOutTime")      case SubmitTask(port, name) => println("SubmitTask")      case HeartBeat(time) => println("HeartBeet")    }  }}case class HeartBeat(time: Long)case class SubmitTask(id: String, taskName: String)case object CheckTimeOutTask

来源：https://www.cnblogs.com/sunnystone85/p/11363659.html

标签

模式匹配

scala