nested for loops and saving data with reduced dimensions

I want to get a resultant matrice with reduced columns: I am using 3 for loops and ine if command. but not getting third loop working properly. Actually

Matric A   (100 x 150)
Matrics with filtered columns B   (100 x 15)

 for i = 1:100;      % rows
    for j = 1:150;    % col
        for SelectedCol = 1 :15;

            if A(i,j)> 1000
                B(i,SelectedCol)  = bb(i,j)  ; ---> how i can do this?
            end

        end
    end
end

Thnaks

[Azzi Abdelmalek]

what is your problem?