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

You can do the following:

(mapA.keys + mapB.keys).associateWith {
    setOf(mapA[it], mapB[it]).filterNotNull().joinToString()
}

1. put all keys in a set
2. iterate over that set and and associate each element with the set of values
3. remove the null values from the value set
4. concatenate the elements in the value list using joinToString().