I have to combine 90 txt files in one txt file

I have to concatenate 90 txt files (001.txt; 002.txt;...) in a single txt file; each of them has two columns, the first column start always from 0 to 299999 (which is time in ms) and the second column has coordinates (positive and negative number). How can I write a script to do that? I will write an example: First file would look like this:

0 -0.015

1 0.003

2 -0.050

.. ....

299999 0.002

Combined file would look like this:

0 -0.015

1 0.003

2 -0.050

.. ....

299999 0.002

300000 -0.015

300001 0.003

.. ....

1000000 0.022

I tried to combine with several software, but they combine the first column from 0 to 299999 every time for each file. If it would not be for the first column there will no be problem.

I really appreciate any kind of help. This will improve my work. Thank you!

Answer 1

[Jon]

If you don't want to create a huge matrix before writing it out you could do this

% define some parameters
outfile = 'alldata.txt' % name for concatenated output file
numFiles = 90; % number of files to be concatenated
numPoints = 299999; % number of data points in file at 1ms intervals



% start the output file with the first datafile
copyfile('001.txt',outfile)

% loop through list of files reading and concatenating (appending)
startTime = 0; % initialize value for starting time
for k = 2:numFiles
    % generate file name of form 001.txt, 002.txt, ...
    filename = [num2str(k,'%03.f'),'.txt'];

    % read the data
    data = readmatrix(filename);

    % increment the start time
    startTime = startTime + numPoints;

    % increment the time column
    data(:,1) = data(:,1) + startTime;

    % append the data (creates file on first pass)
    writematrix(data,outfile,'WriteMode', 'append')
end

[Trinitron]

Thank you very much!

[Jon]

Hi @Trinitron are you the original poster, just another user name? If so, if this answered your question, can you please accept the answer, so that others will know that an answer is available.

[Anton Yo]

@Jon How can I load my txt files into Matlab? I don't have any basic with Matlab. Thank you once again.

[Jon]

In my code above the line, repeated here "loads the txt files into MATLAB"

   % read the data
    data = readmatrix(filename);

[Anton Yo]

So I did like this:

(R24EE00.txt is the name of the first txt file)

It creates the alldata.txt, but with the data of only the first file txt (R24EE00)

% define some parameters
outfile = 'C:\Users\SigviewUser\Desktop\tracce eeg txt 24\alldata.txt' % name for concatenated output file
numFiles = 100; % number of files to be concatenated
numPoints = 299999; % number of data points in file at 1ms intervals
% start the output file with the first datafile
copyfile('C:\Users\SigviewUser\Desktop\tracce eeg txt 24\R24EE00.txt',outfile)
% loop through list of files reading and concatenating (appending)
startTime = 0; % initialize value for starting time
for k = 2:numFiles
    % generate file name of form 001.txt, 002.txt, ...
    filename = [num2str(k,'%03.f'),'.txt'];
    % read the data
    data = readmatrix(filename);
    % increment the start time
    startTime = startTime + numPoints;
    % increment the time column
    data(:,1) = data(:,1) + startTime;
    % append the data (creates file on first pass)
    writematrix(data,outfile,'WriteMode', 'append')

But it gives me an error:

>> Untitled

outfile =

    'C:\Users\SigviewUser\Desktop\tracce eeg txt 24\alldata.txt'

Error using readmatrix (line 157)
Unable to find or open '002.txt'. Check the path and filename or file permissions.

Error in Untitled (line 17)
    data = readmatrix(filename);

How can I solve this error?

Thank you for the patience.

[Jon]

My code followed your original post where you had said the file names were 001.txt, 002.txt etc

If instead the files are of the form R24EE00.txt, R24EE01.txt, etc up to R24EE99.txt, then you need to modify the line of code where the filenames are created to

filename = ['R24EE',num2str(k,'%02.f'),'.txt'];

[Anton Yo]

It worked! However, in some line it gives me NaN values, probably beaacause the column it's too big ( 30 millions values). Thank you very much for helping me !!!

[Jon]

Glad it worked for you. I'm not sure that you are getting NaN's form the column being very large, maybe something else is going on there.

By the way, if in the end you found that this approach was what ended up solving your problem, it would probably be good to mark this as the accepted answer, just for people who might have a similar question. The other answer is good to, it just depends upon what fit your needs most closely.

Answer 2

[DGM]

This is a start. In this simplified example, there are three files, each with three lines.

You might have to tweak the delimiter specification if you want the output to follow some particular format.

nfiles = 3;
D = [];
for f = 1:nfiles
    thisdata = readmatrix(sprintf('test_%03d.txt',f),'range','B:B');
    D = [D; thisdata];
end

D = [(0:numel(D)-1).' D]

D = 9×2

0 -0.0150 1.0000 0.0030 2.0000 -0.0500 3.0000 -0.0250 4.0000 0.0730 5.0000 -0.0300 6.0000 -0.0170 7.0000 0.1930 8.0000 -0.2500

writematrix(D,'cattedfile.txt')