How to change a cell in a table to double ?

Hey,

I am reading in some data and I want to concatenate the read tables with 218 and 220 columns vertically in one big table. Therefore I add 2 columns with nan values to the table with 218 columns.

But I get this error: Cannot concatenate the table variable 'fill2' because it is a cell in one table and a non-cell in another. So I tried str2double in order to get oridinary double.

But then I get this error: To assign to or create a variable in a table, the number of rows must match the height of the table. I dont understand where my mistake is. Maybe someone could help me out with a correct code snippet.

Thanks a lot!

P.S. I also tried some other codes to solve the problem with cell2mat, a for loop etc. ... it didnt really work. They are commented out.

files = dir('plotdata-*');
tab_gesamt = [];
for K = 1:length(files)
    thisfilename = files(K).name;
    opts = detectImportOptions(thisfilename);
    opts = setvartype(opts,{'Var1','Var2'},'string');
    T = readtable(thisfilename, opts);
    x = width(T);
    y = height(T);
    
    %for motor plotdata
    if isequal(x,220)
        T.Properties.VariableNames(219:220)={'fill1','fill2'};
        
        %       for i=1:y
        %       T.fill1(i) = cell2mat(T.fill1(i));
        %       T.fill2(i) = cell2mat(T.fill2(i));
        % if iscell(T.fill1)
        T.fill1 = str2double(T.fill1);
        % elseif iscell(T.fill2)
        T.fill2 = str2double(T.fill2);
        % end
        %       end
        % for i = 1:width(T), if iscell(T.(i)), T.(i) = cell2mat(T.(i)); end, end
        tab_gesamt=[tab_gesamt; T];
    elseif isequal(x,218)
        fill1 = randi(10, [y,1]);
        fill2 = randi(10, [y,1]);
        fill1(1:y) = nan;
        fill2(1:y) = nan;
        T1 = array2table(fill1);
        T2 = array2table(fill2);
        T_new = [T, T1, T2];
        
        
        tab_gesamt = [tab_gesamt; T_new];
        
    end
    
end

clear K

[Peter Perkins]

It's pretty unlikely that anyone can help with just that information. Attach a SMALL example of something like your files, show a small example of what you are starting with and what you want to end up with, and where in your code the error is coming from.

In any case, this

fill1 = randi(10, [y,1]);
fill2 = randi(10, [y,1]);
fill1(1:y) = nan;
fill2(1:y) = nan;
T1 = array2table(fill1);
T2 = array2table(fill2);
T_new = [T, T1, T2];

is much too complicated. If ytou want to add two all-NaN column vectors to T, just assign nan(y,1) to T.fill1 etc. Just like what you did in the isequal(x,22) case.