Extracting a row of data from multiple files and loop into a calculation.

I have 6 separate files each with 3 columns of data with an unknown number of rows. I am trying to use the first row of each file as a line in a new matrix i.e end up with a 6*3 matrix. I want to repeat this for every row until it ends.

Does this make sense? Does anyone know how to do this?

Answer 1

[Guillaume]

Presumably all the files have the same number of rows. Otherwise, you need to specify what to do with the extra rows in some of the files.

filenames = compose('file%d.csv', 1:6);  %name of files to open. Generated however you want. Possibly with dir
filedata = cell(1, numel(filenames));    %cell array to receive arrays of unknown size
%read the content of all the files:
for fileidx = 1:numel(filenames)
   filedata{fileidx} = csvread(fullfile('C:\somewhere', filenames{fileidx}));  %read the file. May need something other than csvread depending on the file
end

%concatenate and permute into desired shape:
filedata = cat(3, filedata{:});  %concatenate into 3D array. Will error if the files are not all the same size
filedata = permute(filedata, [3 2 1]);

The resulting filedata is a numfiles x numcolumns x numrows matrix, so in your case 6 x 3 x unknownnumber. You could split this into a cell array of 6x3 matrices if you really desire:

filedata = squeeze(num2cell(filedata, [1 2]));  %cell array of numfiles x numcolumns matrices