摘要：
一、List1.varlist1=listOf//println//[10,30,50]//筛选listprintln//[5]//筛选list后的个数print//1 //求和print//92.对象里的某个属性求和dataclassStudentfunmain(){valstudent1=Studentvalstudent2=Studentvalstudent3=Studentvarlist=listOfprint//350}3.递归varlist1=listOf//递归调用fold里的n是初始值print二、Set三、Map
一、List
1.
var list1 = listOf(1, 3, 5) // println(list1.map { it * 10 })//[10, 30, 50] //筛选list println(list1.filter { it>3 }) //[5] //筛选list 后的个数 print(list1.count{it>3}) //1 //求和 print(list1.sum())//9
2.对象里的某个属性求和
data classStudent(val name:String,val score:Int) fun main() { val student1 = Student("tom", 100) val student2 = Student("liu", 100) val student3 = Student("li", 150) var list=listOf(student1,student2,student3) print(list.sumBy { it.score }) //350 }
3.递归
var list1 = listOf(1, 3, 5) //递归调用fold(n)里的n是初始值 print(list1.fold(2) { n, s -> n * s })