Scala偏函数

package day02

object ScalaPartialFunction {
  def func(str : String): Int = {
    if(str.equals("a")) 97
    else 0
  }

  /**
    * 偏函数： PartialFunction[参数的类型，返回值类型]
   */
  def func1: PartialFunction[String, Int] = {
    case "a" => 97
    case _ => 0
  }

//  def f1: PartialFunction[Int, Int] ={
  def f1: PartialFunction[Any, Int] ={
    case i: Int => i * 10

  }

  def main(args: Array[String]): Unit = {
    println(func("a"))
    println(func1("b"))

//    var arr = Array(1,2,3,4)
    var arr = Array[Any](1,2,3,4,"hello")
    var arr1 = Array[Int](1,2,3,4)


    val collect = arr.collect(f1)
    arr1.map(x => x * 10)
    arr1.map((x: Int) => x * 10)
    arr1.map(x => x * 10)
    arr1.map{case x: Int => x*10}//编译器在编译的时候会转换成偏函数
    arr1.map(_ * 10)//_代表数组中的每一个元素



    println(collect.toBuffer)

  }

}