集合框架.png

List

不可变集合
val a:List<Int> = listOf(1,2,3,4)
val b:List<String> = listOf("1","2")
可变集合
val c:MutableList<String> = listOf("1","2").toMutableList()
val d:MutableList<String> = mutableListOf("1","2")
可变集合有修改、添加元素的方法
遍历
for (s in c) {
Log.i("shawn","key${s}")
}
取值
var d = c[0]//取第一个元素

Map

不可变
val a:Map<String,String> = mapOf("1" to "2","2" to "3")
可以修改元素
val b:MutableMap<String,String> = mutableMapOf("1" to "2","2" to "3")
遍历
a.forEach{
Log.i("shawn","key{it.value}")
}
取值
var d = c["1"]//放key取value

ArrayList

val d:ArrayList<String> = ArrayList()
for (a in 0..10){
d += "$a"
}
Log.i("shawn",d.joinToString())
添加
+=等价于add()，这是因为Kotlin中的运算符可以重载
删除
d.remove("1")
d -= "2"
Log.i("shawn",d.joinToString())

Pair

var pair1 = "1" to 1
var pair2 = Pair("1","2")
取值
pair1.first//第一个值
pair1.second//第二个值
解构
val (x,z) = pair1

Triple

var a = Triple("1",2,true)
a.first
a.second
a.third
解构
var (s,b,x) = a