MATLAB: Divide a dataset into subsets

indexingsignal processing

Hello everyone
I have a dataset named chan56 which is 1619936×1 and a vector called markers which is 1×202. The vector markers has the events of the dataset chan56 and i want to split chan56 into subets that contain -1200 indexes from each event until +300. I tried
Data = []
DataMatrix =[zeros(1,length(markers)*1500)];
for n =1 :length(chanPOz)
    for i =1:length(markers)
        if markers(i) == chanPOz(n)
            T = chanPOz(n);
            Data = chanPOz(n-1200:n+300);
            DataMatrix = [DataMatrix  DataMatrix+Data];
        end
    end
end
But i cant take the DataMatrix

Best Answer

This is what you're after, I think. No need for a loop over each point in chanPOz
N = numel(markers) ;
% pre-allocate the result:
newData = zeros(N, 1501) ;  % 1 extra !! [x-1200:x+300] are 1501 values
% loop over each marker
for n = 1:N
   idx = markers(n) ; % the n-th index into chanPOz
   newData(n,:) = chanPOz(idx-1200:idx+300); % get the data and store this in the n-th row
end
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