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How do I save data to a TXT file?

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Bernoulli Lizard
Bernoulli Lizard on 5 Sep 2012
Edited: MathWorks Support Team on 5 Jun 2024 at 13:20
How do I save data to a TXT file? I want to create a simple two column text file, where the first column is the data from a n x 1 matrix and the second column is a different n x 1 matrix. I also want column headings in the first row of each column.
  2 Comments
Raghunandan V
Raghunandan V on 4 Oct 2018
Edited: per isakson on 20 Jan 2019
the problem is you are trying to store them in an array whereas you have to store them in a cell array since each file is of different size Try this code
fileName={'new1.txt', 'new2.txt', 'new3.txt'};
%open file identifier
fid=fopen('MyFile.txt','w');
for k=1:length(fileName)
%read the file name as string including delimiters and next lines
List=textread(fileName{1,k},'%s','delimiter','\n');
%arrange them in order of k if you want in a cell array
FinalList{k,1}=List;
%or print them into a file.
fprintf(fid, [cell2mat(List) '\n']);
end
%close file indentifier
fclose(fid)
Yeswanth Kaushik
Yeswanth Kaushik on 8 Jun 2023
try writetable or writecell commands.

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Accepted Answer

José-Luis
José-Luis on 15 May 2024
Edited: MathWorks Support Team on 5 Jun 2024 at 13:20
To write a text file with columns of data that have variable names, use the “writetable” function. First, create the data to write, put it in a table with variable names, and then write the data to text file.
% Create two columns of data
A = rand(10,1);
B = rand(10,1);
% Create a table with the data and variable names
T = table(A, B,'VariableNames',{'A', 'B'});
% Write data to text file
writetable(T,'MyFile.txt')
For more information see:
Write table to file
https://www.mathworks.com/help/matlab/ref/writetable.html
Starting in MATLAB R2019a
, you can also use the "writematrix" function to write a matrix to a file. For example:
M = magic(5);
writematrix(M,"M.txt");
For a complete list of export functions, see:
Supported File Formats for Import and Export
https://www.mathworks.com/help/matlab/import_export/supported-file-formats-for-import-and-export.html
  13 Comments
lafnath p
lafnath p on 14 Nov 2016
how to get the size of data in file
celine azizieh
celine azizieh on 14 Aug 2017
Better to use: fid=fopen('MyFile.txt','wt');
instead of fid=fopen('MyFile.txt','w');
otherwise when opening the file with notepad, there is not return to the line... everything is written on one line.

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More Answers (3)

WAEL Al-dulaimi
WAEL Al-dulaimi on 8 Dec 2017
In case I want to open a text file and I have a loop that each time give me different results {x1, x1...xn}. So how can I save all the data that I got from the loop in different names such as y1, y2 .... etc? And under each one of them, I can find the result that I got. I'll appreciate your help. thank you
  1 Comment
Peter
Peter on 8 Dec 2017
It is unclear form your question what you are trying to loop across. It sounds like your trying to read from a single text file; is this true? In any case you should be able to just assign the value that you read to a new variable. If you know how long each data set is you can preallocate matrices for those variables, but that's not necessarily necessary.

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Ahmed Saeed Mansour
Ahmed Saeed Mansour on 20 Jan 2019
How can we save transient CFD results in a file during running the code?
  1 Comment
Venkatanarasimha Hegde
Venkatanarasimha Hegde on 17 Mar 2023
Its better if you store the time data at different instants along another matrix dimension (possible in C not sure about matlab) or you can concatinate the new data to existing file, so while visualising you can access after the end index of each time instant.

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Paige Kierce
Paige Kierce on 31 May 2020
randA

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