reduceRight

Common
JVM
JS
Native
1.0
inline fun CharSequence.reduceRight(
    operation: (Char, acc: Char) -> Char
): Char

Accumulates value starting with the last character and applying operation from right to left to each character and current accumulator value.

Throws an exception if this char sequence is empty. If the char sequence can be empty in an expected way, please use reduceRightOrNull instead. It returns null when its receiver is empty.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val strings = listOf("a", "b", "c", "d")
println(strings.reduceRight { string, acc -> acc + string }) // dcba
println(strings.reduceRightIndexed { index, string, acc -> acc + string + index }) // dc2b1a0

// emptyList<Int>().reduceRight { _, _ -> 0 } //  will fail
//sampleEnd
}

Parameters

operation - function that takes a character and current accumulator value, and calculates the next accumulator value.