list - 如何提取数据以在Prolog中列出？

Question

我有一个数组 L某种类型，我试图将数据提取到一个数组，例如:

L=[day(sunday),day(monday)]

到

Target=[sunday,monday]

尝试使用 forall并在 Prolog 列表上搜索相关问题。

extract_data_to_list(L,Target) :-
    member(day(Day),L),
    length(L, L1),
    length(Target, L1),
    member(Day,Target).

电流输出:

?- extract_data_to_list([day(sunday),day(monday)],Target).
Target = [sunday, _5448] ;
Target = [_5442, sunday] ;
Target = [monday, _5448] ;
Target = [_5442, monday].

期望的输出:

?- extract_data_to_list([day(sunday),day(monday)],Target).
Target=[sunday,monday]

Answer 1

这是maplist的理想问题:

day_name(day(DayName), DayName).

dates_daylist(Dates, DayList) :-
    maplist(day_name, Dates, DayList).

Maplist 适用 day_name到 Dates 中每个对应的元素对和 DayList .