kotlin开发 for循环

前言

 　　提供一些for循环的使用demo

简单的一个数数for循环

例子1

fun main() {
    for (i in 0..10){
        print("i = $i ,")
    }
}

i = 0 ,i = 1 ,i = 2 ,i = 3 ,i = 4 ,i = 5 ,i = 6 ,i = 7 ,i = 8 ,i = 9 ,i = 10 ,

例子2 不循环最后一位

fun main() {
    for (i in 0 until 10){
        print("i = $i ,")
    }
}

i = 0 ,i = 1 ,i = 2 ,i = 3 ,i = 4 ,i = 5 ,i = 6 ,i = 7 ,i = 8 ,i = 9 ,

降序循环

fun main() {
    for (i in 10 downTo 0){
        print("i = $i ,")
    }
}

i = 10 ,i = 9 ,i = 8 ,i = 7 ,i = 6 ,i = 5 ,i = 4 ,i = 3 ,i = 2 ,i = 1 ,i = 0 ,

跳步循环

fun main() {
    for (i in 0 .. 10 step 2){
        print("i = $i ,")
    }
}

i = 0 ,i = 2 ,i = 4 ,i = 6 ,i = 8 ,i = 10 ,

for循环遍历时获取index

fun main() {
    val list1 = mutableListOf<Data>(Data("可达鸭", 3), Data("皮卡丘", 6), Data("妙蛙种子", 9))
    for ((index, itemData) in list1.withIndex()) {
        println("itemData = $itemData index = $index ")
    }
}

itemData = Data(name=可达鸭, id=3) index = 0 
itemData = Data(name=皮卡丘, id=6) index = 1 
itemData = Data(name=妙蛙种子, id=9) index = 2 

双for循环跳出

fun main() {
    val list1 = mutableListOf<String>("可达鸭", "皮卡丘", "妙蛙种子", "杰尼龟")
    val list2 = mutableListOf<String>("皮卡丘", "小火龙", "宝石海星", "双弹瓦斯")
    loop1@ for (item1 in list1) {
        println("list1 = $item1")
        for (item2 in list2){
            println("list2 = $item2")
            if (item1 == item2){
                break@loop1
            }
        }
    }
}

list1 = 可达鸭
list2 = 皮卡丘
list2 = 小火龙
list2 = 宝石海星
list2 = 双弹瓦斯
list1 = 皮卡丘
list2 = 皮卡丘