In Kotlin, if statements are expressions. So the following code is equivalent:

if (a) b else c
The distinction between expression and statement is important here. In Java/C#/JavaScript, if forms a statement, meaning that it does not resolve to a value. More concretely, you can't assign it to a variable.

// Valid Kotlin, but invalid Java/C#/JavaScript
var v = if (a) b else c
If you're coming from a language where if is a statement, this might seem unnatural but that feeling should soon subside.