private variables in a matlab GUI

Hello,

I'm brand new to Matlab, but am knowledable enough to be dangerous as a coder in general. I'm just looking for a best practice here. I've created a GUI to run tests on a benchtop electronics assembly. In the GUI I would like to change settings, pass them to a function and store the results in an array of structures that contain all my test data.

This in the variable I would like to be my array of structures

  properties (Access = private)
        results;
    end

This is what is executed when the user hits the "runTest" button.

% Button pushed function: RunTestButton
        function run(app, event)

            for x = 1:app.NumberofTestsEditField.Value
                app.results(x) = runTest(app.paramX.Value,...
                                         app.paramY.Value,...
                                         app.paramZ.Value,...
                                          )
                
                pause(app.TimeBetweenTestsEditField.Value);
            end
        end

The error I get is it cannot covert a structure to a double. As stated, I am looking for best practices. runTest does indeed return a structure with some strings, doubles etc. I am presuming it thinks the results variable I defined as a private variable is of type double (I didn't tell it that). Do I just need need to init it as a variable that has the same structure that is being return for runTest()? I don't know how large it is going to be. Appreciate your patience as I am brand new at this :)

Thanks!

Bob

Answer 1

[Steven Lord]

Before you enter the loop, by the way you've defined it the results property of the app is a double array. You can't assign a struct into an element of a double array; MATLAB doesn't know how to perform that conversion.

s = struct('x', 1, 'y', 2, 'z', 3);
x = 1:10;
x(2) = s % error

Conversion to double from struct is not possible.

You could initialize app.results to be a struct either in the definition of the property or as the first line of that method using the struct function.