arrow-fx-coroutines / arrow.fx.coroutines.stream / Stream / zipWithScan

zipWithScan

fun <B> zipWithScan(z: B, f: (B, O) -> B): Stream<Pair<O, B>>

Zips the input with a running total according to S, up to but not including the current element. Thus the initial z value is the first emitted to the output:

import arrow.fx.coroutines.stream.*

//sampleStart
suspend fun main(): Unit =
  Stream("uno", "dos", "tres", "cuatro")
  .zipWithScan(0) { acc, b -> acc + b.length }
  .toList()
  .let(::println) //[(uno,0), (dos,3), (tres,6), (cuatro,10)]
//sampleEnd

See Also

zipWithScan1