kotlin的集合分为可变集合类Mutable和不可变集合类Immutable,List、Set、Map都是不可变集合,与之对应MutableList、MutableSet、MutableMap是可变集合 创建集合 使用listOf()、setOf()、mapOf() 创建不可变的 List、Set、Map 使用mutableListOf()、mutableSetOf()、mutableMap() 创建可变的 MutableList 、MutableSet 、...
Kotlin List is one of the three Collections (List, Set, Map). List is a collection of elements whose position in the collection is preserved, whereas in Set or Map, there is no fixed position/index for an element. Hence, elements in a list can be accessed using index. List is immutabl...
println(map) 1. 2. 3. 4. 5. 6. 从map中移除元素,通过"-="、remove //*** 移除元素 map -= "Haha" map.remove("Jack") println(map) 1. 2. 3. 4. map转其他集合 //*** map转List集合 val toList = map.toList() println(toList) 1. 2. 3. 4.3 map集合遍历 通过forEach方式,有...
// 以键值对的形式出现,键与值之间使用tovalmap1=mapOf("key1"to2,"key2"to3)valmap2=mapOf<Int,String>(1to"value1",2to"value2")valmutableMap=mutableMapOf("key1"to2,"key1"to3)valhashMap=hashMapOf("key1"to2,"key1"to3)// 同Java中的HashMapmap2.forEach{ key,value->println("...
一、List 创建与元素获取 Kotlin中的集合分为两类 , 只读集合 和 可变集合 ; 调用listOf函数 , 可以 直接创建 List 集合 ; 通过[]下标可以 直接获取 List 集合中的元素 ; 代码语言:javascript 代码运行次数:0 运行 AI代码解释 funmain(){val list=listOf("Tom","Jerry")println("${list[0]}")} ...
first() }.mapValues { (_, list) -> list.size } println("Comparing the result with using 'groupBy': ${groupBy == frequencies}.") } </div> Map.toMap() 和 Map.toMutableMap() 这俩函数可以用来简易复制映射: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 class ImmutablePropertyBag(...
First, we create an empty mutable map to store the result. Then, we iterate over each map in the input list.For eachMap, we also iterate over its entries using a nestedfor()loop. Subsequently, we use thegetOrPut()method to either get the current list of values associated with the key...
Map函数API Example: AI检测代码解析 fun getUpperFruits() { val list = listOf("Apple", "Banana", "Orange", "Pear", "Grape", "Watermelon") val newlist = list.map { it.toUpperCase() } for (fruit in newlist) { ...
Precipitation Map Layer Migration From Google Maps to HMS Core Map Kit Pre-release Check App Release HarmonyOS (Java) Service Introduction Version Change History Function Overview Getting Started Preparations Preparing the Development Environment Configuring App Information in AppGallery Conne...
推荐在数据使用data class,会自动生成的get\set\toString\copy\equals\hashcode方法。这些自动生成的方法相对科学合理,在使用HashMap等使用场景下,会非常有用。 data class User( var id: Long, var name: String, var signTime: Long ) 反编译字节码结果(精简部分): ...