scala进阶23-for与模式匹配

object For_Advanced {
  def main(args: Array[String]): Unit = {
    for (i <- List(1, 2, 3, 4, 5)) println(i)

    //index绑定了一个别名,叫Flink,内部是模式匹配,匹配到Flink后设置别名给index
    for(index@"Flink" <- List("Hadoop", "Spark", "Flink")) {
      println(index)
    }

    //for与元祖模式匹配
    for ((language, "Hadoop") <- Set("Scala" -> "Spark", "java" -> "Hadoop")) {
      println(language)
    }

    //类型限定
    for((k, v: Int) <- List(("spark" -> 5), ("Hadoop" -> "hdfs"))) {
      println(k)
    }
  }
}