How to add a column for data in datastore

I have a data store that holds 2,700 files, theses files are activities such (standing, walking, lying,...and etc).

the datastore contains all these files, all files having 3 columns (acceleration of x,y,z).

I want to write a code that can add a fourth column to this datastore depends on the original file name that I have added earlier to this datastore.

I want to do this, to make labeling and prepare my data for classification.

[Anup Thapa]

Hi. I have the same issue/need. What solution worked for you in the end?

Answer 1

[Khushboo]

Hello,

As datastore simply reads the data from a file to a table, you will have to write the modified table back to the datastore. This can be done using something like this:

while hasdata(currentDs)
    [T, info] = read(currentDs);
    % Add a new column to the end of the table
    T.newCol = newColumnToBeAdded; %ensure that it is a cell array
    %Write the new modified file back the table
    filename = ['newfolder/modifiedfile_', num2str(info.Offset), '.csv']; 
    writetable(T, filename);
end

newDs = datastore('newfolder/*.csv');

Hope this helps!