Read a .mat file and write .csv without opening matlab

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I would like to read a ".mat" file and write it out as ".csv" file without opening matlab.
Basically this:
M = dlmread('FileName.mat', '\t', 1, 0);
csvwrite('FileName.csv', M)
but then without opening matlab.
I'm using linux command line.
Thanks!

Accepted Answer

Marc Jakobi
Marc Jakobi on 14 Oct 2016
You won't be able to run a Matlab-file without opening Matlab - unless you use another program that is compatible.
However, you could write a bash script that runs Matlab in a "hidden" mode:
#!/bin/bash
matlab -nodisplay -nodesktop -r "run /path_to_script/my_script.m"
P. S. I wouldn't recommend csvwrite. fprintf is a lot more flexible and faster.
fid = fopen('filename.csv','w');
fprintf(fid, formatSpec, data);
fclose(fid);
  3 Comments
Marc Jakobi
Marc Jakobi on 14 Oct 2016
You have to declare formatSpec as a variable first: According to the data you are writing to the CSV file.
Here's an example:
t = (0:900:31535100)';
P = rand(size(t));
fid = fopen('filename.csv','w');
formatSpec = '%d;%d\n';
fprintf(fid, formatSpec, [t, P]);
fclose(fid);
The formatSpec tells to write two columns of doubles (%d), delimeted with a semicolon. "\n" tells it to start a new line.
If you type
doc fprintf
in Matlab's command window, you will find a description and examples of how to use format operators.
Walter Roberson
Walter Roberson on 14 Oct 2016
You would want
fprintf(fid, formatSpec, [t, P].');
to write t and P into columns.

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More Answers (2)

Michael02139
Michael02139 on 25 Oct 2016
Thanks for all the tips. I'm just lost even after those tips. Which part of the tips are aimed at helping me to read in a *mat file? And which parts are aimed at writing out a *csv file?
  2 Comments
Marc Jakobi
Marc Jakobi on 25 Oct 2016
That was all about writing a CSV file. Loading a MAT file should be trivial:
load('matFileName.mat')
If you don't know which variables are contained in the mat file, you can load it into a struct:
S = load('matFileName.mat');
varNames = fieldnames(S);
etc.
Michael02139
Michael02139 on 25 Oct 2016
Thanks a lot for following up and responding again! That helped! I have it working.

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Walter Roberson
Walter Roberson on 25 Oct 2016
Is the mat file text with tab delimiters or is it a binary file created by save()?
If it is text with tab delimiters then consider just using sed to change the tabs into comma

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