Data types in TABLE

I create a TABLE with different data types.

For example :

sz = [1 6];
vartypes = ["string" "categorical" "categorical" "categorical" "double" "double"];
noms = ["Screening" "Rando" "Side" "Treatment" "CS_T0" "CS_T1"];
data = table('Size', sz , 'VariableTypes' , vartypes, 'VariableNames', noms);
% ...
% Some processing
% ...
writetable(data, 'Résultats.xlsx');

If I understand correctly, I lose necessarily data types when I use writetable. Everything becomes either double or cellstr.

I know that I can overcome this limitation with detectImportOptions or Import Tool but you confirm that there is no way to find types automatically (just with information stored in the xlsx file) ?

A last question with no direct connection, why data types are not stored by default in the properties of the table ?

I find unnatural to get out of the class with varfun(@class,data) to obtain this information.

Thank in advance.

SAINTHILLIER Jean Marie

Answer 1

[Walter Roberson]

Excel itself recognizes:

• numbers (including dates)
• text
• logical
• error such as #VALUE!

Excel is unable to distinguish between character and string, and has no concept of categorical.

[Jean-Marie Sainthillier]

Thank you.