How to properly extract dataset and load in new file? Keep getting error.

I have original dataset from which I have extract subset

% Load original data variable: 100 x 100 x 1000 x 500
folder = 'C:\Users\ABC\Desktop\Raw'; 
dname = "D"; 

X = load(strcat(folder,'\',dname,'_X.mat')); 
X = X.data();

% Extract from variable 10 x 10 x 10 x 10 subset and save
Xs = X(1:10;1:10;1:10;1:10);
save ('D_Xs.mat', Xs)

Now when I open a new file and try to load in the extracted subset I get an error stating no data.

% Loading Ex
folder = 'C:\Users\ABC\Desktop\Raw'; 
dname = "D"; 

X = load(strcat(folder,'\',dname,'_Xs.mat')); 
X = X.data();

[Stephen23]

You data importing uses absolute paths (which is good), but your data exporting does not (which is bad):

save(fullfile(folder,'D_Xs.mat'), Xs)

Using fullfile is recommended over string concatenation.

Answer 1

[Stephen23]

There is no data field because you saved the array using the name Xs. So you need to use the field Xs (and get rid of the superfluous parentheses):

tmp = load(strcat(folder,'\',dname,'_Xs.mat')); 
X = tmp.Xs;
%       ^^ use the correct field name

If you want the variable in the new mat file to be named data, then you need to name it data (and not Xs).

[AAN]

Thank you very much.