I have this code, where 'data' changes its size with every loop and has to be divided into four equal segments. This division has to be stored in variable 'epoch'. storing it in cell variable isn't an option. How can I store differen lengths of data?

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data = y;
seg = y/4;
signal = data(1,:);
for e = 1:4
epoch (e,:) = signal(1+(e-1)*seg:e*seg);
end

Accepted Answer

Guillaume
Guillaume on 4 Dec 2018
epoch = reshape(signal, [], 4).'
No need for a loop.
  6 Comments
Guillaume
Guillaume on 4 Dec 2018
You get this error because you're reusing epoch that you previously created as a double array. You would have avoided this problem if you had preallocated epoch before the loop. It's always a good to preallocate arrays that you're assigning to in a loop. It makes the loop faster, and avoids this type of errors:
epoch = cell(1, 4); %preallocate epoch
for .... your loop as normal
As usual for matlab, there's no need for the loop (and the preallocation):
defaultlength = ceil(numel(signal) / 4);
epoch = mat2cell(signal, 1, [ones(1, 3) * defaultlength, defaultlength + mod(defaultlength, -4)])
The last element of epoch will be up to 3 elements shorter than the previous 3.

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