zipWithNext

Common
JVM
JS
Native
1.2
fun <T> Iterable<T>.zipWithNext(): List<Pair<T, T>>
(source)

Returns a list of pairs of each two adjacent elements in this collection.

The returned list is empty if this collection contains less than two elements.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val letters = ('a'..'f').toList()
val pairs = letters.zipWithNext()

println(letters) // [a, b, c, d, e, f]
println(pairs) // [(a, b), (b, c), (c, d), (d, e), (e, f)]
//sampleEnd
}
Common
JVM
JS
Native
1.2
inline fun <T, R> Iterable<T>.zipWithNext(
    transform: (a: T, b: T) -> R
): List<R>

(source)

Returns a list containing the results of applying the given transform function to an each pair of two adjacent elements in this collection.

The returned list is empty if this collection contains less than two elements.

import kotlin.test.*

fun main(args: Array<String>) {
//sampleStart
val values = listOf(1, 4, 9, 16, 25, 36)
val deltas = values.zipWithNext { a, b -> b - a }

println(deltas) // [3, 5, 7, 9, 11]
//sampleEnd
}