Kotlin ternary operator equivalent

You may have seen the ternary operator in other languages like Java or JavaScript.

A ternary operator allows you to assign a conditional expression to a variable.

For example, the following JavaScript code assigns the value of variable a to myVar only if a contains a truthy value:

let a = 3;
let myVar = a ? a : "else";

console.log(myVar); // 3

If variable a contains a falsy value (like null, false, or undefined) then the string "else" will be assigned to myVar.

Kotlin doesn’t have a ternary operator, replacing the ternary operator with the if..else statement instead.

Here’s the Kotlin equivalent of the JavaScript code above:

var a: Int? = 3
var myVar = if(a != null) a else "else"

print(myVar) // 3

When you replace the value of a with null, the else expression will kick in:

var a: Int? = null
var myVar = if(a != null) a else "else"

print(myVar) // "else"

You don’t need a ternary operator in Kotlin because many control statements like if, else, and when can be used as expressions in Kotlin.

Kotlin allows you to assign the expression result to a variable or return it from a function.

Replacing ternary operator with elvis operator

Alternatively, Kotlin also has the elvis operator that you can use to shorten the if..else syntax.

The elvis operator is a question mark and colon symbol (?:) that can be used to create a conditional expression.

Take a look at the following example of replacing the myVar assignment with elvis operator:

var myVar = if(a != null) a else "else"

// or

var myVar = a ?: "else"

The elvis operator can be used to safely handle assigning the nullable variable a value to myVar.

When the value of a is null, then Kotlin will take the expression on the right side of the elvis operator.

To summarize, Kotlin doesn’t have a ternary operator like in many other traditional programming languages.

You can use the normal if..else statements as expressions and assign the result to a variable, or you can use the elvis operator.