在Scala中映射的可选元组

Question

If I have a List of tuples, I can convert to a map with toMap :

val x = (3 -> 3)
List(x).toMap

and I get

scala.collection.immutable.Map[Int,Int] = Map(3 -> 3)

If I have a List of Optional and try the same I would get an error:

val x = Some(3 -> 3)
val y = None
List(x, y).toMap

<console>:15: error: Cannot prove that Some[(Int, Int)] <:< (T, U).

I want to get the same result. Is it possible?

Answer 1

You can use flatten on the List to remove the None s:

val x = Some(3 -> 3)
val y = None
List(x, y).flatten.toMap

> scala.collection.immutable.Map[Int,Int] = Map(3 -> 3)