kotlin中when的用法

Kotlin中的when语句类似于Java中的switch语句，但提供了更多功能和更强大的表达能力。下面是Kotlin中when语句的用法：

1. 基本用法：

when (x) {
    1 -> println("x is 1")
    2 -> println("x is 2")
    else -> println("x is neither 1 nor 2")
}

2. 多个分支合并：

when (x) {
    1, 2 -> println("x is either 1 or 2")
    else -> println("x is neither 1 nor 2")
}

3. 使用in运算符：

when (x) {
    in 1..10 -> println("x is between 1 and 10")
    !in 10..20 -> println("x is not between 10 and 20")
    else -> println("x is not in any range")
}

4. 使用is运算符：

when (x) {
    is String -> println("x is a String")
    is Int -> println("x is an Int")
    else -> println("x is neither a String nor an Int")
}

5. 使用表达式作为分支：

when {
    x % 2 == 0 -> println("x is even")
    x % 2 != 0 -> println("x is odd")
    else -> println("x is not a number")
}

6. 在when语句中使用lambda表达式：

when (x) {
    in 1..10 -> {
        println("x is between 1 and 10")
        println("x + 1 is ${x + 1}")
    }
    else -> println("x is not between 1 and 10")
}