How to load multiple CSV files and store in an array?

Question

My CSV files are spectra data of the type A1a(1:853,1:853) . Column 1 contains wavelength information, Column 2 contains intensity information.

I have multiple CSV files in a folder, A1a, A1b, A1c.....A1k.csv and I would like to store these files in an array of type A(10,1:853,1:853) using csvread and a for loop.

How can I do this?

Answer 1

You can use dir with dlmread (or csvread , a wrapper for dlmread ) to read in your data. This example assumes the size of each data file is uniform and you know the exact structure of your data:

% Generate some sample data
fID = fopen('A1a.csv', 'w');
fprintf(fID, '%u,%u,%u\n', repmat(1:5, 3, 1));
fclose(fID);

fID = fopen('A1b.csv', 'w');
fprintf(fID, '%u,%u,%u\n', repmat(6:10, 3, 1));
fclose(fID);

fID = fopen('A1c.csv', 'w');
fprintf(fID, '%u,%u,%u\n', repmat(11:15, 3, 1));
fclose(fID);

% Preallocate array if you know for sure how your data is structured
nfiles = 3;
nrows = 5;
ncols = 3;
mydata = zeros(nrows, ncols, nfiles);

% Read in your data
nheaderlines = 0;
nskipcolumns = 0;
filestoread = dir('A1*.csv');

for ii = 1:length(filestoread)
    mydata(:, :, ii) = dlmread(filestoread(ii).name, ',', nheaderlines, nskipcolumns);
end

This gives us mydata as a [5x3x3] array, where mydata(:,:,1) is A1a.csv , mydata(:,:,2) is A1b.csv , and mydata(:,:,3) is A1c.csv .