Make a list of the pair (value1, value2) then split it?

So then I have a

List<Pair<Value1, Value2>>

. How do I then go to

List<Value1>

and

List<Value2>

without just mapping twice again?

But those maps will be cheap, because you're only calling expensiveOperation() once It's possible there's a shorter way, but I can't think of one off the top of my head right now.

I think you could utilize the

partition

method https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/partition.html ?

I thought so, too, but no. That partitions according to a condition. I want to create two lists of the same length using two mapper functions