Question

I need a predicate that given a list of lists (matrix)

removeElementM(Line,Column,List,NewList)

removes the (Line,Column) element.

For example given the List(L):

    ([a,b,c,d],
     [e,r,t,y],
     [u,i,o,t])

removeElementM(2,2,L,X) would return

X = [[a,b,c,d],[e,r,t,y],[u,i,t]]

I already have the stopping predicate

removeElementM(0,0,[[_|T1]|T],[T1|T]).

but cant’t come up with the solution for the other one…

Answer 1

Something like that :

removeElementM(Line,Column,[List | Rest],[List |NewList]) :-
    Line > 0,
    Line1 is Line - 1,
    removeElementM(Line1, Column, Rest, NewList).

removeElementM(0, Column,[List | Rest],[List1 |Rest]) :-
    removeElementL(Column, List, List1).

removeElementL(Column, [H | T], [H | T1]) :-
    Column > 0,
    Column1 is Column - 1,
    removeElementL(Column1, T, T1).

removeElementL(0, [_H | T], T).