How would I best go about producing multiple lists...

# announcements

[diesieben07]

How would I best go about producing multiple lists from a single one? Right now I am doing two map operations after another, but that requires me to do some computations twice. Do I really have to write a for loop and add to two lists?
Example:

val list = listOf(1, 2, 3)
val a = list.map { expensiveOperation(it).value1 }
val b = list.map { expensiveOperation(it).value2 }

[gcx11]

What about chunked? https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/chunked.html

[diesieben07]

Chunked... does something completely different, no?

[gcx11]

Yes, sorry

Why can't you store result of the expensive operation? Like this:

class Foo(val value1: Int, val value2: Int)

fun foo(value: Int): Foo {
    return Foo(value, value * 2)
}

fun main(args: Array<String>) {
    val l = listOf(1, 2, 3)

    val newList = l.map { foo(it) }
    val a = newList.map { it.value1 })
    val b = newList.map { it.value2 })
}

[diesieben07]

Yes, I was looking for a way to do that in one go...