翻译强力驱动I am trying to work out how to remove duplicate elements in a list of lists in Prolog.
E.g:
input: [[1,2,3],[5,6],[3,4],[1,7]]
expected output: [[1,2,3],[5,6],[4],[7]]
I know I can use the predicate sort/2 to remove duplicates in a single list, but how do I get it to work across multiple lists?
Here is my attempt. Hope you've made some attempts to solve it and learn from this...Anyway if you still didn't come up with anything take a look at the following code:
remove_dupl(InL, OutL):- remove_dupl(InL, [], OutL1),remove_empty(OutL1,OutL). remove_dupl([],_,[]). remove_dupl([H|T],L,[[H1]|T2]):- H=[H1], \+member(H1,L), remove_dupl(T,[H1|L],T2). remove_dupl([H|T],L,[[H1|T2]|T3]):- H=[H1|T1], \+member(H1,L), remove_dupl([T1|T],[H1|L],[T2|T3]). remove_dupl([H|T],L,T2):- H=[H1|T1], member(H1,L), remove_dupl([T1|T],L,T2). remove_dupl([H|T],L,[[]|T2]):- H=[H1], member(H1,L), remove_dupl(T,L,T2). remove_empty([],[]). remove_empty([[]|T],T1):-remove_empty(T,T1). remove_empty([[H|T]|T1],[[H|T]|T2]):-remove_empty(T1,T2).Maybe not the most efficient solution. Example:
?- remove_dupl([[1,2,3],[5,6],[3,4],[1,7]],L). L = [[1, 2, 3], [5, 6], [4], [7]] ; false.