我想在Kotlin中使用when()表达式从函数返回不同的值.输入是String，但它可能可以被解析为Int，所以如果可能的话，我想返回解析后的Int，如果不是的话，返回String.由于输入是String，我不能使用is类型判断表达式.
Is there any idiomatic way to achieve that?
Edit: My problem is how the when() expression should look like, not about the return type.
Version 1 (using toIntOrNull and when when as requested)
fun String.intOrString(): Any {
val v = toIntOrNull()
return when(v) {
null -> this
else -> v
}
}
"4".intOrString() // 4
"x".intOrString() // x
Version 2 (using 100 and the elvis operator 101)
when is actually not the optimal way to handle this, I only used when because you explicitely asked for it. This would be more appropriate:
fun String.intOrString() = toIntOrNull() ?: this
Version 3 (using exception handling):
fun String.intOrString() = try { // returns Any
toInt()
} catch(e: NumberFormatException) {
this
}