Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.2k views
in Technique[技术] by (71.8m points)

dynamic - problem with deleting list item in prolog

my code in prolog

:- dynamic kitchenfurniture/1.

kitchenfurniture([furniture(fridge,1), furniture(table,2), furniture(chair,1)]).

writel([H|T]) :- write(H), nl, writel(T).

whatkitchenfurniture :- kitchenfurniture(X), writel(X).

addkitchenfurniture(X) :- kitchenfurniture(Y), append(Y, [X], Z), retract(kitchenfurniture(Y)), assert(kitchenfurniture(Z)).

deletekitchenfurniture(X) :- kitchenfurniture(Y), delete(X, Y, Z),  retract(kitchenfurniture(Y)), assert(kitchenfurniture(Z)).

when I enter the code in the console

enter image description here

it does not remove the item from the list

problem wth line code deletekitchenfurniture(furniture(fridge,1)).

question from:https://stackoverflow.com/questions/65837552/problem-with-deleting-list-item-in-prolog

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

It is difficult to understand what exactly you type into the console; why don't you show it?

It is probable that this is wrong:

?- deleteaddkitchenfurniture('furniture(fridge,1)').

The correct way to do it might be:

?- deleteaddkitchenfurniture(furniture(fridge,1)).

No single quotes there. If you put it in single quotes, it becomes an atom with some parentheses embedded in it. If you don't quote, it is a compound term, as in the original list you have in here:

kitchenfurniture([furniture(fridge,1), furniture(table,2), furniture(chair,1)]).

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...