W3cubDocs

/Kotlin

ifEmpty

Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)
inline fun <C, R> C.ifEmpty(
    defaultValue: () -> R
): R where C : CharSequence, C : R

Returns this char sequence if it's not empty or the result of calling defaultValue function if the char sequence is empty.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val empty = ""

val emptyOrNull: String? = empty.ifEmpty { null }
println(emptyOrNull) // null

val emptyOrDefault = empty.ifEmpty { "default" }
println(emptyOrDefault) // default

val nonEmpty = "abc"
val sameString = nonEmpty.ifEmpty { "def" }
println("nonEmpty === sameString is ${nonEmpty === sameString}") // true
//sampleEnd
}

© 2010–2020 JetBrains s.r.o. and Kotlin Programming Language contributors
Licensed under the Apache License, Version 2.0.
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.text/if-empty.html