Scala: List[Future] to Future[List] disregarding failed futures

Question

I\'m looking for a way to convert an arbitrary length list of Futures to a Future of List. I\'m using Playframework, so ultimately, what I really want is a Future[Resu

Answer 1

Scala 2.12 has an improvement on Future.transform that lends itself in an anwser with less codes.

val futures = Seq(Future{1},Future{throw new Exception})

// instead of `map` and `recover`, use `transform`
val seq = Future.sequence(futures.map(_.transform(Success(_)))) 

val successes = seq.map(_.collect{case Success(x)=>x})
successes
//res1: Future[Seq[Int]] = Future(Success(List(1)))

val failures = seq.map(_.collect{case Failure(x)=>x})
failures
//res2: Future[Seq[Throwable]] = Future(Success(List(java.lang.Exception)))