Convert Either[A, B] to Option[A] where Left becomes Some

Question

I would like to convert an Either[A, B] to an option, such that if Either is Left it is Some[A] , and if it is Right it is None .

So far I've come up with

either.swap.map(Some(_)).getOrElse(None)

which is a bit of a mouthful.

and

either match { 
  case Left(value) => Some(value)
  case Right(_) => None
}

which is fine, but ideally I would like to know if there's a more idiomatic way using methods rather than an explicit match.

Answer 1

Converting Luis's comment to answer we have

either.swap.toOption

For example

val either: Either[String, Int] = Left("Boom")
either.toOption
either.swap.toOption 

outputs

res0: Option[Int] = None
res1: Option[String] = Some(Boom)

where we note either.toOption returns Option[Int] whilst either.swap.toOption returns Option[String] .

_{Apologies for copying in Luis' comment, but IMO it is useful enough to be posted as an answer.}