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

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Sunyoung Lee on 14 Oct 2016
Edited: dpb on 14 Oct 2016
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
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

Marc Jakobi on 14 Oct 2016
Edited: Marc Jakobi on 14 Oct 2016
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

dpb on 14 Oct 2016
Edited: dpb on 14 Oct 2016
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