It is not easy to follow what you are doing here, especially with respect to your using the strings as part of the subscript (that will absolutely not work).
I would do something like this:
dataout(:,1) = filtfilt(bd,ad,data(:)); % Convert To Column Vector, Then Filter
for n=2:nfilters
dataout(:,n) = filtfilt(bd,ad,dataout(:,n-1)); % Store Sucessive Column Vectors
end
datafiltered = dataout; % Define ‘datafiltered’ As ‘dataout’ Matrix
If you do not want to save the entire matrix of intermediate results, do not subscript them.
If you only want to output the final result, do this instead:
datafiltered = dataout(:,end); % Define :datafiltered, As Last Column Of 'dataput' Matrix
Make appropriate changes to get the result you want.
Also consider preallocating the matrix, so before the loop set it to:
dataout = zeros(numel(data), nfilters);
to execute the loop faster.
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