占位符的使用

package spark.demo

object MyApp2 {
  // 部分适用
  def msg (from: String, to: String, text: String) = s"($from -> $to): $text"

  def main(args: Array[String]): Unit = {

    // 使用占位符表示部分参数
    val registor: (String, String) => String        = msg(_: String, "USA", _: String)
    // 使用占位符表示所有参数
    val msgFunc: (String, String, String) => String = msg _

    /**
      * (Tony -> USA): OK!
      * (Jack -> USA): Great!
      * (Alex -> USA): Good!
      */
    println(registor("Tony", "OK!"))
    println(registor("Jack", "Great!"))
    println(registor("Alex", "Good!"))

    /**
      * (Tony -> 80): OK!
      * (Jack -> 100): Great!
      * (Alex -> 90): Good!
      */
    println(msg("Tony", "80", "OK!"))
    println(msg("Jack", "100", "Great!"))
    println(msg("Alex", "90", "Good!"))
  }
}