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

2016 10 14
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更新时间：2016 10 25
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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!

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 采纳的回答

Marc Jakobi
Marc Jakobi 2016-10-14

0 个投票

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);

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Michael02139
Michael02139 2016-10-14
Hi Marc, thanks for your suggestions.
I'm starting with your suggestion to use fprintf and did this:
>> clear all
>> fid = fopen('FileName.mat','w');
fprintf(fid, formatSpec, data);
fclose(fid);
But I get this:
??? Undefined function or variable 'formatSpec'.
Any clue why? (your example text suggests opening a .csv file but I'm starting with .mat...)
thanks,
Marc Jakobi
Marc Jakobi 2016-10-14
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 2016-10-14
You would want
fprintf(fid, formatSpec, [t, P].');
to write t and P into columns.

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更多回答（2 个）

Michael02139
Michael02139 2016-10-25

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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?

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Marc Jakobi
Marc Jakobi 2016-10-25
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 2016-10-25
Thanks a lot for following up and responding again! That helped! I have it working.

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Walter Roberson
Walter Roberson 2016-10-25

0 个投票

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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