Kotlin Tutorial
Kotlin Classes
Kotlin when Expression
You also can use when instead of if..else; when is the conditional expression with multiple branches.
Normal usage of when:
Example:
WHY KOTLIN:
- Kotlin is Easy to learn
- Kotlin is Interoperable with Java and many other languages
- Kotlin is Safe and Concise
- Kotlin is more easier; If you already know Java
- Kotlin is free to use
This tutorial will teach you the most basic fundamentals of Kotlin.
NOT REQUIRED, any prior programming language experience.
when (days) {
1 -> println("Sunday")
2 -> println("Monday")
3 -> println("Tuesday")
// . . . to 7 (Saturday)
else -> {
println("No day exists on that number")
}
}
Using when we match its argument (days) against all of its branches; and when some condition is satisfied that will print or perform a particular function.
The else branch is executed when none of the other conditions get satisfied.
Remember? : The when expression is similar to switch case statement. If you are familiar with Java or other C-like languages you may also be familiar with switch case statement.
Kotlin when as an expression:
Example:
var month = 5
var result = when (month) {
1 -> "January"
2 -> "February"
3 -> "March"
4 -> "April"
5 -> "May"
6 -> "June"
7 -> "July"
8 -> "August"
9 -> "September"
10 -> "October"
11 -> "November"
12 -> "December"
else -> {
"No month exists on that number"
}
}
println("Month is $result"
The code above outputs:
Month is May
Same like the “if” expression; using when as an expression “else” is mandatory.
Learn more about when expression, visit Kotlin when expression.
