kotlin: for的用法之一

一，代码：

例子:

fun forExample1() {
    // Kotlin 集合
    var list : List<String> = listOf<String>("apple", "banana", "kiwifruit")
    println("遍历集合")
    // 遍历list
    for(i in list){
        println("list:"+i)
    }
    for (index in list.indices) {
        val str = "list item at $index is ${list[index]}"
        println(str)
    }
    // 库函数 withIndex() 获取索引
    for ((i, v) in list.withIndex()) {
        val str = "list the element at $i is $v"
        println(str)
    }

    // Kotlin 数组
    //var array : IntArray = intArrayOf(5, 6, 7, 8, 9)
    var array : Array<String> = arrayOf("java", "c plus plus", "kotlin", "python")
    println("\n遍历数组")
    // 遍历数组
    for(i in array){
        println("array:"+i)
    }
    for (index in array.indices) {
        val str = "array item at $index is ${array[index]}"
        println(str)
    }
    // 库函数 withIndex() 获取索引
    for ((i, v) in array.withIndex()) {
        val str = "array the element at $i is $v"
        println(str)
    }

    // map
    val map = hashMapOf<String, String>("name" to "Hili", "age" to "93")
    println("\n遍历map")
    for ((k, v) in map) {
        println("map: $k -> $v")
    }
}

调用:

        //处理按钮点击事件
        binding.button1.setOnClickListener {
            forExample1()
        }

二，运行结果: