list - Prolog file manipulation problem -

i use swi prolog , code this. read data predicate file , arity count can change. how can generalize it. example, if data(a1,b1,c1) writes in file, how can find solution? have idea?

>    basla:-consult('test.pl'), >          answer(l1,l2,l3,l4,l5), >          list_to_set(l1, x), >         >          write(x). >     answer(l1,l2,l3,l4,l5):- >       findall(first, data(first,_,_,_,_),l1), >       findall(second, data(_,second,_,_,_),l2), >       findall(third, data(_,_,third,_,_),l3). 

if arity of predicate seems change, it's better make arity 1 , give list argument. findall queries can extended call nth1 or nth0.