How to remove even numbers in List using Prolog

Question

I need to remove all even numbers in first list and save the rest to second list. My first non-working approach was:

remove_even([],[]).
remove_even([H1|T1],         


        

Answer 1

I mean maybe I read this wrong but don't you think you all way overthought this problem? So taking out all even elements in the first list and storing them in the second list I was able to do that just by skipping over every even element, like so:

remove_evens([], Ys).
remove_evens([X], [X|Ys]).
remove_evens([X,_|Xs], [X|Ys]):-
  remove_evens(Xs, Ys), !.

which in turn would give this result:

| ?- remove_evens([1,2,3,4,5,6,7], List2).
List2 = [1,3,5,7|_]