Re: Counter of elements in prolog

Sied@r schreef:

I'm getting (A,Y)
(2,2) (2,1) (2,1) (3,2) (3,1) (1,1) (3,1) (_G291,0)

So probably a lot more as you want it to produce...

thanks - yep I think this is much more that I need

is there posibility to filter to only uniq answers ?

D.

Maybe one of the following programs is more what you need (for your homework??)...

% longer
count([A|As], B, Y) :-
count(As, A, X, R),
(
Y is X+1,
B = A
;
count(R, B, Y)
).

count([], _, 0, []).
count([A|As], A, Y, R) :- !,
count(As, A, X, R),
Y is X+1.
count([B|As], A, Y, [B|R]) :-
count(As, A, Y, R).

/*
% shorter
count(L, A, Y) :-
sort(L, S),
member(A, S),
sublist('='(A), L, SL),
length(SL, Y).
*/

Cheers,
Peter
.

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