Kotlin Kotlin Ternary Conditional Operator with examples

This post talks about how to write a ternary conditional operator with examples from Kotlin

In Java, ternary operators are written with the following syntax

condition? true_block? false_block

condition is evaluated and executes true_block if true, else false_block is executed.

There are no conditional operators in Kotlin. We can use conditional expressions such as if, when and try syntax

Kotlin Ternary Conditional Operator examples

Using if blocks

We can write a simplified version in a single statement.

if (conditional_expression) block1 else block2

Conditional expressions are evaluated, executes block1 if the condition is true, else block2 is executed. For example,

val number = -20
 if(number>0) "+ve" else "-ve"

assign the if expressions to a variable,

val number = -20
var numberString = if(number>0) "+ve" else "-ve"

java does not allow assigning if the expression results in a variable.

using when

when used to construct the similarity of if and else blocks in a readable way. Here is a syntax

when(condition) {
    expression1 -> block1
    expression2 -> block2
}

Here is an example

val number =1
when (number) { 
    1 -> print("1") 
    0 -> print("0") 
    else -> {  
        print("Not 0 and 1") 
    } 
}

using the Elvis operator for checking nullable variables

This is useful for null checking with simplified expressions. variable1 =variable2 ?: value

the left side of the ?: operator is a variable or expression and checked for null, if it is not null, return it, else return the right side of ?: i.e value.

if variable 2 is not null, return variable2 if variable2 is null, returns value.

Here is an example

val a=null
val b=20;
val c= a ?: b

The same can be written using the below

vale c=if ( a != null ) a else b

Kotlin - Ternary

Kotlin Ternary Conditional Operator examples