Basically I planned on getting the first three elements and also the last three and then concatenate them together. This has been a hassle. I know something like this first([A, B, C|_]) can help me get the first three. apart from this I am completely stuck. I am a noob at prolog, please help.
Given a relation first_last(L1, L2),
when I write something like first_last([1,2,3,4,5,6,7,8,9], L2) . where L2 is the resulting list, i should get L2 = [1,2,3,7,8,9]
Define a relation first_last(L1, L2) which takes a list L1 and returns a list L2 containing the first three and last three elements of L1
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1 Answers
first_last(Xs, [A,B,C,X,Y,Z]) :-
phrase(( [A,B,C], ..., [X,Y,Z] ), Xs).
... --> [] | [_], ... .
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