Could you please tell me algorithm how to chose numbers in a matrix which is sastified a condition?

for example,i have a matrix a=|1 2 3;3 4 6;8 9 13| i want to chose value numbers between 2 and 5, so i get a12=2;a13=3;a21=3;a22=4;I also know the address of number. But with large matrix, how to get? thanh you so much

Answer 1

[Mischa Kim]

Luc, use

 a         = [1 2 3;3 4 6;8 9 13];
 [row col] = find(a>= 2 & a<=5);

which will give you the row and colum indices of the numbers you are looking for. To filter out the individual values and assign them to a new matrix, you could use

 aa = a(find(a>= 2 & a<=5));

[Luc Nguyen]

It is fast and nice!Could you please tell me your algorithm?

[Mischa Kim]

This code snippet does the same thing and should give you enough to get started:

 a    = [1 2 3;3 4 6;8 9 13];
 llim = 2;
 ulim = 5;
 kk   = 1;
 for ii = 1:length(a(:,1))      % row index
    for jj = 1:length(a(1,:))   % col index
        if a(ii,jj) >= llim && a(ii,jj) <= ulim
            val_ind(kk,:) = [ii jj a(ii,jj)];
            kk            = kk + 1;
        end
    end
 end