How to set a let to display a numerical value in App Design?

I recently migrated my gui from guide to app design. Everything was working prior to the move. one last (hopefully) issue i am facing is updating the text on a label to a numberical value returned by numel() function.

error is :

Error using matlab.ui.control.internal.model.mixin.MultilineTextComponent/set.Text (line 49)

'Text' must be a character vector, or a 1-D array of the following type: cell array of character vectors, string, or categorical.

The code :

while strcmp(value,'On')
                  [plyX, plyY] = ginput(2);                                          %% prompt the user to click two points. (Care needs to be taken to fist click the lower left corner and then select upper right corner)
                     width = abs(plyX(1) - plyX(2));                                    %%Compute width 
                     height = abs(plyY(1) - plyY(2));                                   %%Compute height
                     rec = rectangle('Position',[plyX(1) plyY(1) width height]);
                     [in,on] = inpolygon(app.X,app.Y,plyX,plyY); 
                     inon = in | on;                                                    %%Ammend point in and on the edge of the rectangle
                     idx = inon(:);                                                     %%get all the indeces of the points in the polygon
        %                  [ptsx get_in]=numpoints(plyX,plyY,laser1_pts);                     %%using numpoints function just for comparison
                     xcoord = app.X(idx);                                           %%get the X coordinates of the poits in the polygon
                     PointsInSelection = numel(xcoord);                 %%get the number of points
        %                  PointsInSelection2 = get_in;                               %%get the number of points
                     app.Label.Text = PointsInSelection;
        %                  display(handles.PointsInSelection2);
                     pause(3);
                     delete(rec);
             end

Answer 1

[Adil Ali]

I used

app.Label.Text = string(numericalValue);

compared to

app.Label.Text = numericalValue;

And it worked!

Not sure why App design had to make things complicated! it is so simple to code without it. Its almost like programming in Java!

[Rik]

Just like all other parts of Matlab: it matters what the data type is. You can't mix up the value of a variable and the representation of that value in a character vector or string scalar

v1=10;
v2='10';
v3="10";
%all 3 are different (although v2 and v3 are similar in many ways)