Question

我无法在一小时内完成最后一个问题

reverseDrop(L,R) :-
   reverseDrop(L,1,[],R).

reverseDrop([HL|TL],N,I,R) :-
   N = 1,
   reverseDrop(TL,0,[HL|I],R).

如何完成此代码，因此它会反转列表并删除2个元素中的1个：

?- reverseDrop([3,1,5,2,7,3],L).
L = [ 7, 5, 3 ].
true

?- reverseDrop(['world','a',' hello'],L).
L = [ 'hello', 'world' ].
true

Answer 1

As StackOverflow is not for doing homework or tests，当时我们都不会做彼此的课堂作业，没有人会在你的时间里提出你的问题！我问Prolog专家（那些已经实现它的人）和这个小宝石回来了，并且为了后来的读者的利益而展示：

reverseDrop([],[]). %this can catch the empty list, when we have run out of data

reverseDrop([Keep|Rest1],Out):- %take the first item in the list off the main input list,
    append([_Drop],Rest,Rest1), %removes one item from what is left in the list, to be discarded
    reverseDrop(Rest,Reply), % recurse on the remainder
    append(Reply,[Keep],Out). % attach the First item to the end of the previous output
reverseDrop([Keep],[Keep]). % this is to catch when a list started with an odd number

在Prolog中反转并删除

1 个答案: