Kotlin 循环
假定有一个数组
val array = arrayOf("Welcome", "Come", "to", "Kotlin", "World", "!")
1. for 循环
for (word in array) {
println(word)
}
Welcome
Come
to
Kotlin
World
!
- 如果在循环时带上索引值，可以这样写
for ((index, value) in array.withIndex()) {
println("$index --> $value")
}
或者是这样
for (couple in array.withIndex()) {
println("${couple.index} --> ${couple.value}")
}
0 --> Welcome
1 --> Come
2 --> to
3 --> Kotlin
4 --> World
5 --> !
for 循环执行的机制
class MyIterator(var iterator: Iterator<Int>) {
operator fun next(): Int {
return iterator.next()
}
operator fun hasNext(): Boolean {
return iterator.hasNext();
}
}
class MyList {
private val list = ArrayList<Int>()
fun add(value: Int) {
list.add(value)
}
operator fun iterator(): MyIterator {
return MyIterator(list.iterator())
}
}
fun main(args: Array<String>) {
var list = MyList()
list.add(1)
list.add(2)
list.add(3)
for (value in list) {
println(value)
}
}
2. while 循环
while 循环与 Java 的用法一样，不做详细介绍
