kotlin-stdlib/kotlin.sequences/chunked

chunked

fun <T> Sequence<T>.chunked(size: Int): Sequence<List<T>>(source)

Splits this sequence into a sequence of lists each not exceeding the given size.

The last list in the resulting sequence may have fewer elements than the given size.

Since Kotlin

1.2

Parameters

size

the number of elements to take in each list, must be positive and can be greater than the number of elements in this sequence.

The operation is intermediate and stateful.

Samples

import kotlin.test.*

fun main() { 
   //sampleStart 
   val words = "one two three four five six seven eight nine ten".split(' ')
val chunks = words.chunked(3)

println(chunks) // [[one, two, three], [four, five, six], [seven, eight, nine], [ten]] 
   //sampleEnd
}
fun <T, R> Sequence<T>.chunked(size: Int, transform: (List<T>) -> R): Sequence<R>(source)

Splits this sequence into several lists each not exceeding the given size and applies the given transform function to an each.

Since Kotlin

1.2

Return

sequence of results of the transform applied to an each list.

Note that the list passed to the transform function is ephemeral and is valid only inside that function. You should not store it or allow it to escape in some way, unless you made a snapshot of it. The last list may have fewer elements than the given size.

Parameters

size

the number of elements to take in each list, must be positive and can be greater than the number of elements in this sequence.

The operation is intermediate and stateful.

Samples

import java.util.Locale
import kotlin.test.*

fun main() { 
   //sampleStart 
   val codonTable = mapOf("ATT" to "Isoleucine", "CAA" to "Glutamine", "CGC" to "Arginine", "GGC" to "Glycine")
val dnaFragment = "ATTCGCGGCCGCCAA"

val proteins = dnaFragment.chunked(3) { codon: CharSequence -> codonTable[codon.toString()] ?: error("Unknown codon") }

println(proteins) // [Isoleucine, Arginine, Glycine, Arginine, Glutamine] 
   //sampleEnd
}