Prolog中的关联列表 [英] Associative Lists in Prolog

问题描述

我的任务是实现带有列表的地图.我们定义关联列表如下:

my task is to implement maps with lists. We defined associative lists as follows:

[]是列表， k是键，v是一个值，a是一个关联列表，然后[[k, v] | a]是一个关联列表.

[] is the list, k is a key, v is a value and a is an associative list, then [[k, v] | a] is an associative list.

因此，现在我必须写一个谓词，在该谓词中检查给定的参数是否为关联列表. 例如:

so now ive got to write a predicate, in which it checks if the given argument is a associative list. for example:

?- test([[a,5]]). -> true., ?- test([[1],[2]]). -> false.

我真的很沮丧，我希望有人能在那帮助我

im really in despair, i hope someone can help me there

问候

推荐答案

我可以说

I may say that associative lists in SWI-Prolog are implemented as an AVL-trees, not as the lists of a dotted pairs, though the latter is possible.

所以，让我们尝试一下.

So, let's try your way.

[]是列表，k是键，v是值，a是关联列表，则[[k，v] | a]是一个关联列表.

[] is the list, k is a key, v is a value and a is an associative list, then [[k, v] | a] is an associative list.

一项更正:

我建议[[ k | v ] | a]更加紧凑并且更具关联性")

I'd suggest [[ k | v ] | a] that is more compact and is "more associative" )

is_assoc([]).
is_assoc([[K|V] | AL]) :- %corrected 29 apr 2018 19:00 gmt+3
    !, is_assoc( AL ).


put(KV, AL, AL0) :-
   KV = [K|V],
   get(K, AL, V),
   remove(KV, AL, AL_KV),
   put(KV, AL_KV, AL0).

put(KV, AL, [KV | AL]).

get(K, AL, V):-
   member([K|V], AL).

这篇关于Prolog中的关联列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！