[scala] scala 函数 (⑦)

Posted 2020-09-13 xwolf

1.scala 函数定义

2.scala 高阶函数

3.匿名函数

4.柯里化

 

import scala.math._

/**
  * @author xwolf
  * @date 2017-04-24 9:57
  * @since 1.8
  */
class Function {
   // _ 将round 方法转化为函数
   val  cel = round _

   def add(x:Int,y:Int) = x+y

   //函数
   def f(x : => Int) = x.+(3)

   def m (r : => Double) = {
      val rs=(Math.PI*r*r*0.5)
      rs}

   //高阶函数
   def a(s:(Int)=>Int,z:Int)= s(z)+this.f(z)

   //匿名函数定义
   val minus = (m:Int) => m-1

   // 柯里化函数定义
   def ads(x:Int)=(y:Int) => x*y

   //阶乘 (递归实现)
   def sm(x:Int):BigInt={
      if (x==1 || x==0) 1
      else sm(x-1)*x
   }

   //阶乘 (reduceLeft 实现)
   def rsm(x:Int):BigInt={
      (1 to x).reduceLeft(_ * _)
   }

   // 求数组的最大值
   def max(ary :Array[Int]):Int={
      ary.reduceLeft(_ max _)
   }

   // 求数组的最大值
   def getMax(ary :Array[Int]):Int={
      //底层也是reduceLeft
      ary.max
   }
}

 

测试:

object FunctionTest {

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

    val function = new Function
    val cel = function.cel(32)
    println(cel)
    val a = function.f(1)
    println(a)
    val b = function.add(12,32)
    println(b)
    val c = function.m(2.4)
    println(c)

    val d = function.minus(3)
    println(d)
    //柯里化
    val e = function.ads(2)(10)
    println(e)

    val f = function.sm(5)
    println(f)

    val f2 = function.rsm(5)
    println(f2)

    val ary =Array(3,32,4,2,2)
    val g =function.getMax(ary)
    println(g)

    //高阶函数使用
    val af = function.a(a=>4,3)
    print(af)
  }

}