MATLAB: Testing if an input is numeric or character

Question

Hi folks, i'm implementing a software on appDesigner and i want to prevent wrong entries from users.

I've tried to use the folowing code but it's not working. My gol would be, check if the user entered with a number or character. If it's a number then OK, otherwise open a warning dialog box informing the error and then stop the program.

I don't know how to get the logical answer of "teste_potencia" and use it!

The way i've writed it's not working.

           Sbase_gerador = str2double(strrep((app.potencia.Value),',','.')); 
           
           teste_potencia = isnumeric(Sbase_gerador)
            
            if ~teste_potencia
                opts= struct('WindowStyle','modal','Interpreter','tex');
                potencia_incorreta = warndlg('\fontsize{11}Caracteres diferentes de números não são aceitos.',...
                    'Entrada incorreta de dados', opts);
                app.potencia.Value='0';
            end

Answer 1

if isnan(Sbase_gerador)
    ...
end