how can I store for loop result in different row(for each i) and column(for each j given i)?

this code results in 1*n matrix giving output in a same row altogether. however, I would like to have result divided into different rows for the same given i

for example, if i=19, result should appear in the first row and if i=20, result should appear in the second row and so on

[num, txt, raw] = xlsread('all1month.xlsx');
stock = [];    
for i = 19:35;
  for j = 2:5677;
    if strcmp(raw(i,j), raw(231,4));
      stock = [stock raw(i,j+1)];
    end
  end
end

thanks

Answer 1

[Marc Jakobi]

You could do it like this:

stock = nan(17,5676);
 rCT = 0; %row counter
 cCT = 0; %column counter
 maxC = 0; %for shortening (column counter sizes may vary)
 for i = 19:35
     rCT = rCT + 1;
     for j = 2:5677
         if strcmp(raw(i,j), raw(231,4))
             cCT = cCT + 1;
             maxC = max(cCT, maxC);
             stock(rCT, cCT) = raw(i,j+1);
        end
     end
    cCT = 0; %reset column counter
 end
stock = stock(1:rCT, 1:maxC); %shorten to used values

I would recommend to initialize variables with their maximum possible size and shorten them afterwards. If it's a small data set, you won't notice much of a difference and if it is a large data set, you will avoid having long calculations, only to get an "out of memory" error after hours of the program running.

Another way could be to only increment the row counter if your condition is met:

    stock = nan(17,5676);
     rCT = 1; %row counter
     cCT = 0; %column counter
     maxC = 0; %for shortening (column counter sizes may vary)
     incRow = false;
     for i = 19:35
         for j = 2:5677
             if strcmp(raw(i,j), raw(231,4))
                 incRow = true;
                 cCT = cCT + 1;
                 maxC = max(cCT, maxC);
                 stock(rCT, cCT) = raw(i,j+1);
            end
         end
         if incRow
            rCT = rCT + 1;
         end
        incRow = false; %reset incRow
        cCT = 0; %reset column counter
     end
    stock = stock(1:rCT-1, 1:maxC); %shorten to used values

Answer 2

[dpb]

Keep another index variable incremented for the purpose--

...
k=0;
for i = 19:35;
  k=k+1;
  accum = [];    
  for j = 2:5677;
    if strcmp(raw(i,j), raw(231,4));
      accum = [accum raw(i,j+1)];
    end
    stock{k} = accum;
  end
end

NB: stock is a cell array because its length may be different by row...

Alternatively, w/o the data to check for certain, it appears you could shorten the above significantly as

k=0;
for i = 19:35;
  k=k+1;
  ix=strcmp(raw(i,:), raw(231,4));  % logical vector where found
  stock{k}=raw(i,ix);               % save the found locations
end