Parallel operations on Kotlin collections?

Question

In Scala, one can easily do a parallel map, forEach, etc, with:

collection.par.map(..) 

Is there an equivalent in Kotlin?

Answer 1

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 { ... } 

Answer 2

As of Kotlin 1.1, parallel operations can also be expressed quite elegantly in terms of coroutines. Here is pmap on lists:

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

Note that coroutines are still an experimental feature.