Error in append dot structure mat file

Dear all, I have data store in a mat file (i.e.,subject01_dataset.mat) . Under the mat file, each data were store 1) Patient_FullData.auxilaryData 2) Patient_FullData.reshape

After some processing, I want to store the result as Patient_FullData.result Thus the following line were utilized

save ('SC4001E0_dataset.mat', 'Patient_FullData.result', '-append');

However, I got the following error

'Patient_FullData.data' is not a valid variable name.

May I know how to mitigate this issue

Answer 1

[Walter Roberson]

You cannot save() a field in a structure, and you cannot use save() to appened to an existing struture.

If you need to appened on to an existing array in a .mat file, consider using matFile()

[balandong]

Thanks for the info. In fact, by using this line, MATLAB does not load any data from the MAT into memory but which is memory efficient. Thanks

[Walter Roberson]

matFile() is the defined way to append to an existing variable in a .mat file.