How to change variable name in MAT file

Hi!

I wrote a code which make some files *.mat. All files were made with loop, therefore every file have one variable inside with same name but different contain. And when a load mat files to the next script every file change the variable contain from previous file.

Of cours I can open every file and change the variable name manualy, but how can I automatize this process?

Thanks a lot for the answer.

[Walter Roberson]

It is often easier to code processing of files in a loop if the variable name is the same.

[Stephen23]

"All files were made with loop, therefore every file have one variable inside with same name but different contain."

What you describe is good data design. Much much better than having a different variable name in every MAT file.

"Of cours I can open every file and change the variable name manualy, but how can I automatize this process?"

Why all the effort just to ruin good data design and make your data harder to work with?

What would you do with lots of separate variables in the workspace? Processing them will be harder, slower, and much uglier:

https://de.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Solution: keep the variables the same, just like all experiences MATLAB users would do.

Learn to LOAD into an output variable:

S = load(...);

and store the imported data in one array using indexing, just as the MATLAB documentation shows:

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

Then you can write simple, robust, efficient MATLAB code.

What you are proposing is the opposite. Best avoided.

Answer 1

[Fangjun Jiang]

Save the .mat file as what it is from the source. Use a=load('*.mat') to load it. "a" would be a structure. The variable is in a.VarName.

[Andrey Melnikov]

as a variant...

[Fangjun Jiang]

??

[Andrey Melnikov]

I mean that I tried, it works, thanks

Answer 2

[Walter Roberson]

You could modify the File Exchange Contribution https://www.mathworks.com/matlabcentral/fileexchange/42274-loadfixnames-loads-a-mat-file-fixing-invalid-names to patch .mat variable names.

This is not something I would recommend. For many purposes, the situation you have now with the same variable name in each file is easier to deal with.

http://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

[Andrey Melnikov]

"This is not something I would recommend. For many purposes, the situation you have now with the same variable name in each file is easier to deal with. "

I understand but the next stage I need to use content from each variable together simultaneously.

Thanks a lot

[Stephen23]

"...the next stage I need to use content from each variable together simultaneously."

That is easier, more robust, and more efficient when the variable name/s are exactly the same in every MAT file.

Import the data into one array (which could be a container array, e.g. structure or a cell array), which will make processing your data simpler and more efficient than trying to process lots of variables. This is exactly what the MATLAB documentation shows:

https://www.mathworks.com/help/matlab/import_export/process-a-sequence-of-files.html

Having them in one array makes using them "simultaneously" trivial.