1.List集合 

 1.1 只读List

fun main() {val list = listOf("Jason", "Jack", "Jacky")println(list.getOrElse(3){"Unknown"})println(list.getOrNull(3)?:"Unknown")
}

 1.2 可变List

fun main() {val mutableList = mutableListOf("Jason", "Jack", "Jacky")mutableList.add("Jimmy")mutableList.remove("Jack")mutableList.forEach(::println)val toList = mutableList.toList()println(toList===mutableList)}

 

1.2.mutator函数

fun main() {val mutableList = mutableListOf("Jason", "Jack", "Jacky")mutableList += "Jimmy"mutableList -= "Jason"mutableList.removeIf{it.contains("Jack")}println(mutableList)}

 1.3. 遍历元素

fun main() {val list = listOf("Jason", "Jack", "Jacky")for (s in list) {println(s)}list.forEach{println(it)}list.forEachIndexed { index, s ->println("$index $s")}
}

 1.4 解构语法过滤元素

fun main() {val list = listOf("Jason", "Jack", "Jacky")val(zeroIndexEnum,_,twoIndexEnum)=listprintln(zeroIndexEnum)println(twoIndexEnum)}

2. Set

2.1 只读Set

 

fun main() {val set = setOf("Jason", "Jack", "Jacky", "Jack")val elementAt = set.elementAt(2) //这里用这个方法取下表val elementAtOrNull = set.elementAtOrNull(5)//这个方法下表越界了，不会抛异常而是给nullprintln(elementAt)}

2.2 可变Set集合 

fun main() {val set = mutableSetOf("Jason", "Jack", "Jacky", "Jack")set+="Jimmy"println(set)}

 2.3 集合转换与快捷函数

fun main() {val set = mutableSetOf("Jason", "Jack", "Jacky", "Jack")set+="Jimmy"println(set)val listOf = listOf("Jason", "Jack", "Jacky", "Jack")val toList = listOf.toSet().toList()//不是一个对象了val distinct = listOf.distinct()//不会修改原集合println(listOf)println(distinct)}

3.数组类型

 

import java.io.Filefun main() {val intArray:IntArray = intArrayOf(10, 20, 30)val toIntArray:IntArray = listOf(10, 20, 30).toIntArray()val array:Array<File> = arrayOf(File("xx"), File("xx"))}

4.Map 

4.1 Map的创建

fun main() {val map:Map<String,Int> = mapOf("Jack" to 20, "Jason" to 18, "Jack" to 30)mapOf(Pair("Jimmy",20),Pair("Jason",16))}

4.2 读取Map的值

fun main() {val map:Map<String,Int> = mapOf("Jack" to 20, "Jason" to 18, "Jack" to 30)println(map["Jack"])println(map.getValue("Jack"))println(map.getOrElse("Rose"){"Unknown"})println(map.getOrDefault("Rose",0))}

 

4.3 Map的遍历

fun main() {val map:Map<String,Int> = mapOf("Jack" to 20, "Jason" to 18, "Jacky" to 30)map.forEach{println("${it.key}, ${it.value}")}map.forEach { (key: String, value: Int) ->println("$key $value")}
}

 4.4 可变Map集合

fun main() {val map:MutableMap<String,Int> = mutableMapOf("Jack" to 20, "Jason" to 18, "Jacky" to 30)map += "Jimmy" to 30map.put("Ji",3)val orPut = map.getOrPut("Rose") { 18 }//如果没有就添加进去println(map)}