Save with identical file- and variable name

I am saving data in Matlab to open it in a python script. For some reason this requires that the name of the variable and the filename are the same. For example, this works (saving as version 7.3 makes it possible to import in python without losing the structure):

data = data.(filename{1,1})
save('data', 'data', '-v7.3')

but this only allows me to save with the filename 'data' , which I can also not change afterwards, because then python won't read the file anymore.

I know I could use this method to save each file manually with a name that I want, but there is quite a large number of files involved. So I would like to re-write it in a way that uses the filename stored in the array filename automatically. I have the feeling this should be possible, but I can't get it to work yet...

I have tried many things like this:

for i = 1:n
    filename = (filename{1,i});
    name = strcat(filename);
    name = data.(filename{1,i})
    save(name, 'name', '-v7.3')
end

But for some reason it seems not to be possible to save a file with a filename that is identical to the variable name. I hope my problem is clear, any ideas would be greatly appreciated!

[Stephen23]

"For some reason this requires that the name of the variable and the filename are the same"

I use numpy and scipy all the time at work, and its importing routines do NOT require the filename and the variable names to be the same (how would that even work for multiple variables?):

https://docs.scipy.org/doc/scipy/reference/generated/scipy.io.loadmat.html

https://docs.scipy.org/doc/scipy/reference/tutorial/io.html

Whatever routine you are using is very very badly written if that really is the case, and you would be better off fixing the problem there, rather than trying to write hack MATLAB code to fix a problem in some Python code.

Note that dynamically accessing variables names is how beginners force themselves into writing slow, complex, buggy code. Read this to know why:

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

It is much more efficient to use indexing, fieldnames, or the columns/rows of a table.

[Aagje E]

I tried to fix the problem in python first by using scipy, the thing is that within the file I try to save as 'data', there are multiple variables (data/time, data/distance, etc.) and that this structure with the headers for each variable gets lost using scipy. That is why I prefer saving using '-v7.3', which saves the .mat in the same way as an hfd5, which is an easier file format. And normally with the h5py these are easy to read in python.

I am a beginner in Matlab, which is why I would rather have my data in python ;)

Answer 1

[OCDER]

Assuming your Data is a structure containing your variables, here's one way to make file names = variable names:

Data = struct('A', 1, 'B', 2, 'C', [1 2 3], 'D', [1 3 ; 3 4]); %Example structure of data
Fields = fieldnames(Data);
for f = 1:length(Fields)
    save(Fields{f}, '-v7.3', '-struct', 'Data', Fields{f});
end

[Aagje E]

Thank you! So easy to implement and short :)