kotlin高级特性

解构：

class User(var age:Int, val name:String){
    operator fun component1() = age
    operator fun component2() = name
}


fun main() {
    val (age, name) = User(18, "Jame")

val nameAddrssMap = mapOf<String, String>("Jame" to "China", "Alice" to "US")
for ((name, address) in nameAddrssMap){
    println(name)
    println(address)
}

}

 作用域函数：

 

 

 

 集合操作符

 

 

协程

 

fun main() = runBlocking {
    val job = launch {
        repeat(1000) { i ->
            println("挂起中$i")
            delay(100L)
        }
    }//已经开始执行

    val job2 = async {
        delay(100L)
        return@async "你好"
    }

    delay(200L)
    println("main:主线程等待中")
    job.cancel()
    job.join()
    println("main:即将完成退出")
    println(job2.await())//调用await才开始执行
}