Question

我是Prolog的新手，我需要从列表中删除重复项，如下例所示。

?- remove([a,a,b,c,a,a,b,c,b,a,a],X).
X = [a,b,c,a,b,c,b,a]

Answer 1

如果我理解正确，您需要删除 adjacents 重复项。只需复制跳过第一个相邻元素的元素。我会让你完成代码......

remove([X,X|Rest], [X|Rest1]) :-
   !,   % this commit avoid the logical alternative you'll code below
   .... % recurse to get Rest1 from Rest
remove([X|Rest], [X|Rest1]) :-
   % recurse to get Rest1 from Rest
% remember the base case !!

编辑，因为错误指出，这样的天真删除/ 2是错误的。我已经更正了添加一个remove / 3谓词，它会对证人进行复制核算，即使用元素预测。

remove([X|Xs], [X|Ys]) :-
  remove(X, Xs, Ys).
remove(X, [X|Xs], Ys) :-
  !,  % discard the duplicate
  ... % recurse to get Ys from Xs, with same witness
remove(_, [X|Xs], [X|Ys]) :-
  ... % the cut above ensure that here we must change witness when recursing
% as always, remember the base case !!

从列表序言中删除相邻的重复项

1 个答案: