merge/union two string sub arrays inside a json array kotlin

Question

is there anyway we can merge/union the two sub arrays inside a json array

 jsonArray = [["abc","hello","hai"]["true","false","hai"]]

 expected output would be ["abc","hello","hai","true","false"]

any help would be highly appreciated!

Thanks

Answer 1

You could first flatten it and then turn it into a Set to remove duplicates. For example:

val jsonArray = listOf(listOf("abc","hello","hai"), listOf("true","false","hai")) // This is the same as [["abc","hello","hai"]["true","false","hai"]]

val flattenedSetOfJsonArray = map.flatten().toSet()

println(flattenedSetOfJsonArray) // prints [abc, hello, hai, true, false]

• Edit

If you want to flatten deeply nested lists you can use this helper method (credits to)

fun List<*>.deepFlatten(): List<*> = this.flatMap { (it as? List<*>)?.deepFlatten() ?: listOf(it) }

Now use this method like this:

val jsonArray = listOf(listOf("abc","hello","hai"), listOf("true","false","hai"), listOf(listOf("true", "false", "abc")))
val flattenedSetOfJsonArray = jsonArray.deepFlatten().toSet()

println(flattenedSetOfJsonArray) // prints [abc, hello, hai, true, false]