Save uniquely named variables in loop to a certain location

Hello everyone,

I am running a loop where a variable U is calculated and saved in a .mat file under a unique name every iteration. To name the .mat file I use sprintf:

 for j:length(d)
    % Long calculation of U left out
    save(sprintf('U%02d',j+1), 'U',  '-v7.3');
  end

Each U is now saved in a .mat file named with the iteriation number with two digits after 'U' and in mat version 7.3. This works great.

However, I would also like define the folder location where the .mat file is saved. I know how to do this using the save command without sprintf but I can't seem to get this to work in combination with sprintf.

Any help is greatly appreciated,

Thank you, Roel

Answer 1

[Stephen23]

Do NOT concatenate paths/directories. The recommended method is to use fullfile:

fullname = fullfile(dir1path,dir2path,...,filename)

This will automatically take into account the required file separators. For your case, something like this:

sdp = some directory path
for k = 1:numel(d)
    % Long calculation of U left out
    fnm = sprintf('U%02d.mat',k+1); 
    save(fullfile(sdp,fnm), 'U', '-v7.3')
end

[Roel]

Thank you,

I had never heard of fullfile, great!

[Stephen23]

@Roel: you should use fullfile, as it handles the file separator quite nicely.

Answer 2

[KSSV]

path = pwd ;     % Give your path here 
filename = [pwd,filesep,sprintf('U%02d',j+1)]

By the way, you need not save data of iteration into different .mat files. You can save them into a 3D matrix or cell and save it into a singl mat file.

[Stephen23]

Do NOT use path as a variable name: this will shadow the important inbuilt function of that name.

It is recommended to use fullfile rather than concatenating strings, e.g.:

https://www.mathworks.com/matlabcentral/answers/373789-i-m-having-a-fid-1-and-i-don-t-know-why-or-how-to-fix-it-please-help#answer_297038

https://www.mathworks.com/matlabcentral/answers/343350-how-to-save-multiple-plots-in-one-folder#comment_459243

[Roel]

Thanks KSSV, this solves my problem.

I want different .mat files because of RAM issues. Saving the data into one matrix or mat causes an 'out of memory error' on my system.

Thanks again!

[KSSV]

Still...you can append data into single mat file...