/**
* filter
* 过滤器
* filter(函数)
* 如果函数的返回值为True, 则元素被保留下来
*
*/
def main(args: Array[String]): Unit = {
// 把数值为偶数的留下来
val arr1 = Array(1,2,3,4,5)
// val arr2 = arr1.filter(x=> {
// // println(x)
// x%2 == 0
// })
val arr2 = arr1.filter(x => x%2==0)
arr2.foreach(println)
var score = Array(90,98,60,49,100)
// 把小于80分的值去掉。只保留大于80分的分数
score.filter(x =>80).foreach(println)
元素累加
def main(args: Array[String]): Unit = {
val arr = Array(1,2,3,4,5)
// 求数组元素的累加
val rst = arr.reduce( (x,y)=> x + y )
//val rst = arr.sum
println(s"rst = ${rst}")
reduce 用法
// reduce ==== reduceLeft 从左往右计算
// reduceRight 从右往左计算
def main(args: Array[String]): Unit = {
val arr = Array(1,2,3)
val rst = arr.reduceLeft( (x,y)=> x - y )
val rst1 = Array(1,2,3,4).reduceRight( (x,y)=> x - y )
println(s"rst = ${rst}")
println(s"rst = ${rst1}"
