Switch in Kotlin is known as when expression. It allows you to check different cases based on a value. Here's an example of how to use a when expression in Kotlin:
val day = 3
when (day) {
1 -> println("Monday")
2 -> println("Tuesday")
3 -> println("Wednesday")
4 -> println("Thursday")
5 -> println("Friday")
else -> println("Weekend")
}
In the above example, we check the value of the variable day and print the corresponding day of the week. If the value doesn't match any of the cases, the else block is executed which prints "Weekend".
You can also perform multiple operations in a single case:
val month = 3
when (month) {
1, 3, 5, 7, 8, 10, 12 -> println("31 days")
4, 6, 9, 11 -> println("30 days")
2 -> println("28 or 29 days")
else -> println("Invalid month")
}
In the above example, we check the value of the variable month and print the number of days it has. Multiple values can be checked together separated by commas.
You can also use when as an expression:
val result = when (day) {
1 -> "Monday"
2 -> "Tuesday"
3 -> "Wednesday"
4 -> "Thursday"
5 -> "Friday"
else -> "Weekend"
}
println(result)
In the above example, the when expression returns a value based on the value of day. This value is stored in the variable result and then printed. If none of the cases match, the value returned is "Weekend".