A More Powerful getOrElse?

Question

I have the following code:

val userName = users.get(userID) match {
  case Some(user) => user.name
  case None => "Invalid User ID"
}

Is there a more concise way of writing this?

I was wondering if there was something similar to getOrElse that would let me apply a function if it is successful (to extract the user name), or return a plain value otherwise.

Answer 1

scala> Map("a" -> 1).get("a").fold("invalid user id")("value:"+_)
res15: String = value:1

scala> Map("a" -> 1).get("b").fold("invalid user id")("value:"+_)
res16: String = invalid user id

Option.fold has some problems with type inference, for potential pitfalls see another answer.