how to get the output of an if statement in a matrix

Hello-- I have a question and it is very important to me. I will appreciate if anyone could help me on this issue! WE have two matrices: one is r(40*80) and the other one is s(8*1) Also we know that 8 rows of matrix r are zeros. ( for example : rows number 6,9,19,23,25,32,33,38 )

I need a code to just write the numbers of zero rows ( which are listed above ) in the s matrix in the order. I wrote this:

s=zeros(8,1);

for row_number = 1:40

    A=r(row_number,:);
     [i,v,c]=find(A);
     row_number; 
     max(v);
     min(v);
     c;

     if isempty(max(v))
        for h=1:8

       s(h,1)=row_number;
       hold on
        end
           s 

   end

and this is the answer I got!

s =

     6
     6
     6
     6
     6
     6
     6
     6

s =

     9
     9
     9
     9
     9
     9
     9
     9

s =

    19
    19
    19
    19
    19
    19
    19
    19

s =

    23
    23
    23
    23
    23
    23
    23
    23

s =

    25
    25
    25
    25
    25
    25
    25
    25

s =

    32
    32
    32
    32
    32
    32
    32
    32

s =

    33
    33
    33
    33
    33
    33
    33
    33

s =

    38
    38
    38
    38
    38
    38
    38
    38

What I need to have is simply an answer with this form : s =

    6
    9
    19
    23
    25
    32
    33
    38

the reason I use find(A) was to do some calculations with min(v) and max(v) for rows with non zero elements. I will be thankful of anyone helping me with this. Best, Homayoon

Answer 1

[Guillaume]

I have no idea what you're trying to do with your code (in particular why is there a hold on which is to do with graphics?), but the answer is simply:

s = find(all(r == 0, 2));

e.g:

r = randi([0 10], 40, 80); %demo data
r([6,9,19,23,25,32,33,38], :) = 0; %fill rows 6,9, etc. with 0

s = find(all(r == 0, 2))

outputs:

s =

     6
     9
    19
    23
    25
    32
    33
    38

[Homayoon]

Oh thanks, I really appreciate your quick answer :D