Prolog：删除最后一个列表元素

Question

我成功反转了一个清单：

reverse([],Z,Z).
reverse([H|T],Z,A) :- reverse(T,Z,[H|A]).

我想要一个删除列表最后一个元素的程序。

Answer 1

为什么你需要改变任何东西？

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% remove_last(IN_LIST, OUT_LIST).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% 1. No last element to remove, fail - cut stops alternatives
remove_last([], []) :- !, fail.

% 2. Only one element in list - return empty list - cut stops alternatives
remove_last([_], []) :- !.

% 3. If the rules above did not match, preserve the head of the
% list in the result list and recurse...
remove_last([X | T], [X | T2]) :-
    remove_last(T, T2).