Kotlin when expression example
Checkout the kotlin when expression example.
WHAT IS KOTLIN?
Kotlin is a general-purpose, statically typed, and open-source programming language. It runs on JVM and can be used anywhere Java is used today. It can be used to develop Android apps, server-side apps and much more. Google accepetd the kotlin as the officill language for android.
HISTORY OF KOTLIN
Kotlin was developed by JetBrains team. A project was started in 2010 to develop the language and officially, first released in February 2016. Kotlin was developed under the Apache 2.0 license.
FEATURES OF KOTLIN
- Concise: Kotlin reduces writing the extra codes. This makes Kotlin more concise.
- Null safety: Kotlin is null safety language. Kotlin aimed to eliminate the NullPointerException (null reference) from the code.Interoperable.
- Interoperable: Kotlin easily calls the Java code in a natural way as well as Kotlin code can be used by Java.
- Smart cast: It explicitly typecasts the immutable values and inserts the value in its safe cast automatically.
- Compilation Time: It has better performance and fast compilation time.
- Tool-friendly: Kotlin programs are build using the command line as well as any of Java IDE.
- Extension function: Kotlin supports extension functions and extension properties which means it helps to extend the functionality of classes without touching their code.
Let’s see a simple example of when expression.
- fun main(args: Array<String>){
- var number = 4
- var numberProvided = when(number) {
- 1 -> “One”
- 2 -> “Two”
- 3 -> “Three”
- 4 -> “Four”
- 5 -> “Five”
- else -> “invalid number”
- }
- println(“You provide $numberProvided”)
- }
We can use multiple branches of condition separated with a comma. It is used, when we need to run a same logic for multiple choices.
- fun main(args: Array<String>){
- var number = 8
- when(number) {
- 3, 4, 5, 6 ->
- println(“It is summer season”)
- 7, 8, 9 ->
- println(“It is rainy season”)
- 10, 11 ->
- println(“It is autumn season”)
- 12, 1, 2 ->
- println(“It is winter season”)
- else -> println(“invalid input”)
- }
- }
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