MATLAB: Assign values to a new variable via a function

MATLABvariables

I have a repetitve task that I want to turn into a function. The process that I am repeating at the moment for many variables is:
   load('names_v1.mat')
   names_v2 = names_v1;
   save('names_v2','names_v2')
To turn this process into a function the bit I am struggling with is line two. That is in the below function the line namesNew = namesOld will obviously not work becuase namesOld is the string with the variable name and not the variable itself. I was trying to use the variableValues function but that doesn't seem appropriate
function test = fileRet(oldVersion, newVersion)
   % old verion might be 'v1'
   % new version might be 'v2'
   
   namesOld = strcat('names_', oldVersion);
   namesNew = strcat('names_', newVersion);
   
   load(namesOld)
   
   % Below line is the line that doesn't work
   namesNew = namesOld;
   
   save(namesNew,namesNew)
   
end
Any ideas

Best Answer

"% Below line is the line that doesn't work"
namesNew = namesOld;
It doesn't work because you are trying to magically access variable names using strings, which is certainly possible, but it is one way that beginners force themselves into writing slow, complex, buggy code that is hard to debug. Read this to know why:
https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval
Writing better (simpler, more robust, less buggy) code makes this task easier. For example, you should always load a .mat file into an output variable (which is a structure):
S = load(...);
Working with fields of a structure is much easier than magically accessing variable names, so lets try that:
S = load(namesOld);
C = struct2cell(S);
T = cell2struct(C,namesNew,1);
save(namesNew,'-struct','T')
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