Problems with fprintf format (Matlab)

I want to correct variables' format in a txt file, using the next code (previous import as separated arrays: skipping the first row (with text headers), defining date as a string):

id = fopen('data.txt', 'w');
fprintf(id, '%5s %3s %3s %3s %4s %3s %6s\n',...
'fecha', 'dia','mes', 'ano', 'hora', 'min', 'abs370');

datos = cat(2,dia, mes, ano, hora, min1, abs370);
datos = datos';
fecha = Fecha'; % Imported as a string 

fprintf(id, '%16s %2i %2i %4i %2i %2i %8.4f\n',...
    fecha, datos);
    
fclose(id);
type data.txt

But I get this error:

Error using fprintf Unable to convert 'string' value to 'int64'.

Why do I get this error?

Answer 1

[Star Strider]

You have R2020a.

Use writetable instead.

[Isaac Hormigo]

Ok, thanks. But why do I get this error? Is it not posible to mix both format in this way?

[Star Strider]

My pleasure!

No.

Some file formats will allow that, the reason I suggest writetable. It will do all that for you.

Also, if you want to import everything, readtable is the best option. (The documentation for it is linked at the end of the writetable documentation page.)