Creating a manual distinct function without using the distinct command itself. getting there, have a function that works, but the “asc” part changes the order of the entries which makes the solution invalid.
{x where (x?x)=til count x} is a translation of the classic APL ((V?V)=??V)/V Alternatively ‘key group’ but that’s cheating.
APL teachers used to set problems like this as training exercises. APL has symbols where q has keywords. So for example, the APL equivalent of iasc is ?. They were known as dead key problems, as in what would you do if this or that key didnt work?