Parallel operations on Kotlin collections?

You can use this extension method:

suspend fun <A, B> Iterable<A>.pmap(f: suspend (A) -> B): List<B> = coroutineScope {
    map { async { f(it) } }.awaitAll()
}

See Parallel Map in Kotlin for more info

The Kotlin standard library has no support for parallel operations. However, since Kotlin uses the standard Java collection classes, you can use the Java 8 stream API to perform parallel operations on Kotlin collections as well.

e.g.

myCollection.parallelStream()
        .map { ... }
        .filter { ... }

As of Kotlin 1.1, parallel operations can also be expressed quite elegantly in terms of coroutines. Here is a custom pmap helper function for lists:

fun <A, B>List<A>.pmap(f: suspend (A) -> B): List<B> = runBlocking {
    map { async(Dispatchers.Default) { f(it) } }.map { it.await() }
}