Kotlin基础集合类型

Posted 2022-12-03 大雄童鞋

集合基本这3大类型

Array 有序可重复
Set 无序不重复
Map无序可重复

//默认数组10个1

var lists = Array<Int> (10,1)

//创建数组

//数组不可改变(类似Java中的Arrays.asList())
var list = arrayOf(10,1,2,6,7,8,9)
var set = setOf<Int>(77,88,99)
var map = mapOf<Int, Int>(Pair(1,2), Pair(4,5))

for (a in listt) 
    //println(a)

for (b in list) 
    //println(b)




//创建1~5的数组
var list3 = Array(5, i->i+1)
for (b in list3) 
    //println(b)

常用方法

//计数
println(list.count())
println(list.size)
//空
println(list.isEmpty())
println(list.isNotEmpty())
//第一个
println(list.first())
//最后一个
println(list.last())
//第一~第五
println(list.component1())
println(list.component2())
println(list.component3())
println(list.component4())
println(list.component5())

//去重复
println(list.distinct())
//去重复
println(list.toSet())
//切割数组(1<=index<=2)
list.sliceArray(1..2)

//可变数组,上面的数组不可改变

var muList= mutableListOf(11,22,33)
var muList2 = mutableListOf(1,2,3)
var muMap= mutableMapOf(Pair(1,2))
var muSet= mutableSetOf(1,1,1,2)
muList.add(4)
muList.removeAt(1)
muMap.put(3,3)
muMap.remove(3)
muSet.add(5)
muSet.remove(2)

//是否包含某个元素，
muList.contains(1)
muMap.contains(1)
muSet.contains(1)
//包含另一个set
muList.containsAll(list44)

//转化为可变
list.toMutableList()

//转化为数组
set.toTypedArray()
//转化为可变
set.toMutableSet()

//组合,数据合并
var all = list.union(set).union(list4)
print("哈哈"+all)

//根据key得到值
var value = map.get(2)
var elseValue = map.getOrElse(2, 333)
//所有的key和value
var mapKeys = map.keys
var mapValues = map.values
//是否存在key或者value
var booKey = map.containsKey(1)
var booValue = map.containsValue(2)