Getting 'Argument must contain string error' error when saving, it's always worked before

Here is a short piece of my code.

queue = '\Q0';
Case = '\02';
path = 'D:\Data';
folder4Mfiles = strcat(path,'\Raw',queue,Case);    % this corresponds to a location on my computer, I've never had trouble saving with this folder name before

cd(folder4Mfiles)
filename = sprintf('E%d.dat',ti);   % Set filename as the E file of current time step
disp('E file is loading')           % just what we call the files, they are just .dat format
InputData=load(filename);           % Load the E file of current time step
disp('E file is done loading')

M = 352;
N = 92;
P = 352;

X = reshape(InputData(:,1),M,N,P);

save([folder4Mfiles,'\Position_File.mat'],X)

But now I get this error.

Error using save

Argument must contain a string.

I don't understand? [folder4Mfiles,'\Position_File.mat'] is a string

Answer 1

[Geoff Hayes]

Nathaniel - perhaps the error is with the second input parameter

save([folder4Mfiles,'\Position_File.mat'],X)

where you should be passing the name of the variable to save rather than the variable itself. In that case, the above would become

save([folder4Mfiles,'\Position_File.mat'],'X')

Also, consider using fullfile to build your path with filename like

save(fullfile(folder4Mfiles,'Position_File.mat'),'X')

[Nathaniel H Werner]

It looks like both you and Jan gave the same answer, off by a minute. It's been a while since I've used this code, so I think this is a case of forgetting some of the syntax rules.

As to whether to use the variable 'path' or not, I think to be safe I will just call it Path or PATH or some other rendition of the name moving forward.

Thank you!