How to combine hundreds of CSV files in Matlab?

Hi all,

I have LOTS of data in CSV files and I'd like to create one massive master CSV file. How can I combine all of the CSV files into one? Each CSV file has a header with time, type of data, etc. They all have the same number of columns but differet numbers of rows.

Answer 1

[Voss]

Here's an example of how to do it (with 2 files):

input_path = '.'; % location of .csv files
output_file = 'result.csv'; % name of file containing combined data

% read each .csv file into a table stored in a cell array of tables 
% called 'all_data':
file_info = dir(fullfile(input_path,'*.csv'));
full_file_names = fullfile(input_path,{file_info.name});
n_files = numel(file_info);
all_data = cell(1,n_files);
for ii = 1:n_files
    all_data{ii} = readtable(full_file_names{ii});
end
% check the tables:
all_data{:}

ans = 4×2 table
    time    type 
    ____    _____

     0      {'A'}
     1      {'B'}
     2      {'C'}
     3      {'B'}

ans = 3×2 table
    time    type 
    ____    _____

     0      {'B'}
     1      {'A'}
     2      {'C'}

% concatenate all the tables into one big table, and write it to
% output_file:
writetable(cat(1,all_data{:}),output_file);

% check that the resulting output file exists:
dir('*.csv')

data_1.csv  data_2.csv  result.csv  

% check the contents of the resulting output file:
readtable(output_file)

ans = 7×2 table
    time    type 
    ____    _____

     0      {'A'}
     1      {'B'}
     2      {'C'}
     3      {'B'}
     0      {'B'}
     1      {'A'}
     2      {'C'}

[SETIAWATI]

I try to use your example for my exercise but once I run the code. The matlab can not read the "writetable(cat(1,all_data{:}),output_file);" part. Can you tell me why? Because I already try everything but I have not figure it out.