如何通过kotlin编写一个示例函数？

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javafun theAnswer()=42

fun transform(color: String): Int=when (color) { Red -> 0 Green -> 1 Blue -> 2 else -> throw IllegalArgumentException(Invalid)}

fun theAnswer() = 42

实际上等于

fun theAnswer ():Int{
return 42;
}

类似java的switch逻辑分支函数

fun transform(color: String): Int = when (color) {
"Red" -> 0
"Green" -> 1
"Blue" -> 2
else -> throw IllegalArgumentException("Invalid color param value")
}

等于

fun transform(color: String): Int {
return when (color) {
"Red" -> 0
"Green" -> 1
"Blue" -> 2
else -> throw IllegalArgumentException("Invalid color param value")
}

如果用java表达 那么是

public int transform(String color){
switch(color){
case "Red"
return 0;
case "Green";
return 1;
case "Blue":
return 2;
default:
throw new IllegalArgumentException("Invalid color param value");
}
}