'Merging 3 immutable maps in scala

I have 3 immutable maps

as: Map[UUID, A]
bs: Map[UUID, B]
cs: Map[UUID, C]

and I want to merge them so the result is of type:

Map[UUID, (Option[A], Option[B], Option[C])]

What is the best way to do this. And by best I mean fewest lines of code.

scala scala-cats

Solution 1:^[1]

Probably you could use for comprehension:

for {
  k <- as.keySet ++ bs.keySet ++ cs.keySet
} yield (as.get(k), bs.get(k), cs.get(k))

Solution 2:^[2]

Ideally, you want a better data type that knows that at least one of the elements has to be defined. And since you mentioned cats you may do this:

import cats.syntax.all._

val result = ((as align bs) align cs)

That gives you a Map[UUID, Ior[Ior[A, B], C]] which properly represents that the result can either be a single element, a pair, or the three.

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Source: Stack Overflow

Solution	Source
Solution 1	gianluca aguzzi
Solution 2	Luis Miguel MejÃa SuÃ¡rez

'Merging 3 immutable maps in scala

Solution 1:[1]

Solution 2:[2]

Sources

Related Questions

Solution 1:^[1]

Solution 2:^[2]