Hey guys. I need to make parallel `flatMap` in Kot...

# announcements

[Бежан Александр]

Hey guys. I need to make parallel flatMap in Kotlin. How to do that ?
For example:

val coll: List<Set<Int>> = ...
coll.flatMap{set -> setOf(set, set + 1)}

[Бежан Александр]

SO question https://stackoverflow.com/questions/52329152/how-to-do-parallel-flatmap-in-kotlin

[gildor]

Parallel? Kotlin doesn’t provide any threading out of the box

[Бежан Александр]

I’m allowed to use coroutines

[gildor]

Yes, you can use coroutines

[gildor]

I will send an example of such code

[Бежан Александр]

Thanks.

[gildor]

https://stackoverflow.com/questions/52329152/how-to-do-parallel-flatmap-in-kotlin/52329256#52329256

[gildor]

You need something like this

[Бежан Александр]

Thanks that’s what I needed.

[Бежан Александр]

@gildor One more question if you don’t mind. I tested the code and it closes threads and not finishes execution, because threads are closed (showing as ‘park’ state in VisualVM) and async can’t start new coroutines.

[gildor]

@Бежан Александр Which dispatcher do you use? Is your code is blocking? My code should works properly with new dispatchers, but with old one it depends on what operation does
You can use new IO dispatcher if your operation is blocking (just add IO as argument of async)