Multiple file reading

Question

I have more than 10,000 csv file in one folder and file names are 0,1,2,3... like that. I would like to read them and write into one file for further processing.I tried this

files= dir('C:\result\*.csv');
outs = cell(numel(files),1) 
for i = 1:numel(files)   
out{i} = csvread('%i',2,0) 
end 

but it didn't work.

Answer 1

Rather than reading them in as csv files, I would just read in the raw files and write them out again. This will likely be much faster.

files = dir('C:\result\*.csv');
filenames = fullfile('C:\result', {files.name});

% Sort the files based on their number
[~, ind] = sort(str2double(regexp(filenames, '[0-9]+(?=\.csv$)', 'match', 'once')));
filenames = filenames(ind);

% Open the file that you want to combine them into
outfile = 'output.csv';
outfid = fopen(outfile, 'wb');

for k = 1:numel(filenames)
    % Open each file
    fid = fopen(filenames{k}, 'rb');

    % Read in contents and remove any trailing newlines
    contents = strtrim(fread(fid, '*char'));

    % Write out the content and add a newline
    fprintf(outfid, '%s\n', contents);

    % Close the input file
    fclose(fid);
end

fclose(outfid);