How can I view numeric array elements in edit text box, in Guide?

In a simple form I would like to display the primes in specified range (in the edit text box "vypis_prvcsl") . I use the edit text control, but it sends the error:

Error using matlab.ui.control.UIControl/set
While setting property 'String' of class 'UIControl':
Value must be a character array, numeric array, or cell array.
Error in untitled4>pushbutton1_Callback (line 114)
    set(handles.vypis_prvcsl, 'String', a2)
Error in gui_mainfcn (line 95)
        feval(varargin{:});
Error in untitled4 (line 42)
    gui_mainfcn(gui_State, varargin{:});
Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)untitled4('pushbutton1_Callback',hObject,eventdata,guidata(hObject)) 
Error while evaluating UIControl Callback

The code used for pushbutton: function pushbutton1_Callback(hObject, eventdata, handles)

    a1 = (str2double(get(handles.min, 'String'))) : (str2double(get(handles.max, 'String')));
    a2 = isprime(a1);
    a3 = numel(a1(a2));
    set(handles.rozsah, 'String', a3);
    set(handles.vypis_prvcsl, 'String', a2)

Answer 1

[Stephen23]

a2 is of type logical, and is definitely not string, numeric, or cell array. Did you read the error message?

One simple fix is to make convert it to numeric by appending the plus operation:

set(handles.vypis_prvcsl, 'String', +a2)

[Jan]

The implicit conversion by the + operator might be confusing. Perhaps this is "easier":

set(handles.vypis_prvcsl, 'String', num2str(a2))

[Jozef Javorka]

Stephen, thank you for your answer - but the edit text field disappeared and reply

"Warning: Single line Edit Controls can not have multi-line text".

Jan, it works properly, thank you very much (with little edit, but on my side).

set(handles.vypis_prvcsl, 'String', num2str(a1(a2)))