what is the best way to process a list and produce...

# getting-started

[nkiesel]

what is the best way to process a list and produce a new list with potentially fewer elements? I know I could do listOf(1,2,3).mapNotNull { if (it %2 != 0) "hi ${it}" else null } but (a) that relies on null never being a valid result element and (b) does not work for flatMap. Perhaps I should just use a classical for loop and add to the result list?