```val listA = listOf("A","B","C","D","E","F","G",...

# getting-started

[Daniele B]

val listA = listOf("A","B","C","D","E","F","G","H","I","J","K","L")
val listB = listOf("C","E","H","K")

I would like to run the function myfunc(String) on all elements of listA that are not on listB.
What is the most idiomatic way in Kotlin to achieve that?

[Laertes Moustakas]

One way you could do it:

listA.filter { it !in listB }.forEach(::myfunc)

Or map(::myfunc) instead of forEach, depends on whether you want to store whatever myfunc outputs in a new list.

[Daniele B]

many thanks!

[Saharath Kleips]

(listA - listB).forEach(::myfunc) works for what I believe you’re asking for as well I believe

[Daniele B]

great @Saharath Kleips!!!

[Laertes Moustakas]

Oh, sweet! I didn't know Collections used the minus() operator function.