Merge values in map kotlin

Question

I need merge maps mapA andmapB with pairs of \"name\" - \"phone number\" into the final map, sticking together the values for duplicate keys, separated

Answer 1

I would write something like

fun Map.mergeWith(another: Map): Map {
  val unionList: MutableMap = toMutableMap()
  for ((key, value) in another) {
    unionList[key] = listOfNotNull(unionList[key], value).toSet().joinToString(", ")
  }
  return unionList
}

val mergedMap = mapA.mergeWith(mapB)