Finding facts of a template which has something in common with another template - clips

Question

I am using CLIPS for a project.
I am using this template A which has an attribute model and another template B which has an attribute model as well.
So what I want to achieve is based on the attribute model, return those facts of template A which has the same attribute model value as of facts from template B.
I tried using this format
(find-all-facts((?a template_A)(?b template_B))
(and
//condition to be met
)
)
it does give me the results, but it is giving me both the results for A and B which are duplicates.. How do I make it in a way it returns non duplicate values, either A or B?

Answer 1

CLIPS>
(deftemplate template_A
(slot model))
CLIPS>
(deftemplate template_B
(slot model))
CLIPS>
(deffacts start
(template_A (model 1))
(template_A (model 2))
(template_A (model 3))
(template_B (model 2))
(template_B (model 3))
(template_B (model 4)))
CLIPS>
(deffunction extract-every-nth-value (?values ?start ?increment)
(bind ?rv (create$))
(while (<= ?start (length$ ?values))
(bind ?rv (create$ ?rv (nth$ ?start ?values)))
(bind ?start (+ ?start ?increment)))
(return ?rv))
CLIPS> (reset)
CLIPS> (facts)
f-0 (initial-fact)
f-1 (template_A (model 1))
f-2 (template_A (model 2))
f-3 (template_A (model 3))
f-4 (template_B (model 2))
f-5 (template_B (model 3))
f-6 (template_B (model 4))
For a total of 7 facts.
CLIPS>
(find-all-facts ((?a template_A)(?b template_B))
(eq ?a:model ?b:model))
(<Fact-2> <Fact-4> <Fact-3> <Fact-5>)
CLIPS>
(extract-every-nth-value
(find-all-facts ((?a template_A)(?b template_B))
(eq ?a:model ?b:model))
1 2)
(<Fact-2> <Fact-3>)
CLIPS>