Why does this give me the "Unable to perform assignment because the left and right sides have a different number of elements." error?

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Edoardo Modestini 2023-6-5

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编辑： Image Analyst 2023-6-6

Hi,

I'm trying to convert my code into an app as an exercise. I'm trying to get a list to update its items to contain all components.

function CreateComponentButtonPushed(app, event)
            new_comp = comp(app.ComponentNameEditField.Value, length(app.components)+1, app.MolarMassgmolEditField.Value);
            new_comp.setAntoine([app.AntoineEqnAEditField.Value, app.AntoineEqnBEditField.Value, app.AntoineEqnCEditField.Value]);
            app.components = [app.components, new_comp];
            display_names = zeros(length(app.components), 1);
            for i = 1:length(display_names)
                %Set the current value to the name of the component
                display_names(i) = app.components(i).name;
            end
            disp(display_names);
            
            %Supposed to change the list in the app to contain all the new
            %display names
            app.ComponentsListBox.Items = display_names;
end

This is throwing up an error in the display_names(i) = app.components(i).name line. What's the issue here?

Thanks in advance.

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Answer 1

Harsh Saxena 2023-6-5

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Hi,

Maybe this error is occuring due to the fact that app.components.name(i) is a character array, so MATLAB considers left hand side as a double value while the right hand side as an array of characters. Try initializing the display_names as:

display_names = strings([length(app.components), 1]);

Hope this helps!

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Answer 2

Image Analyst 2023-6-6

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编辑：Image Analyst 2023-6-6

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Perhaps make it a cell array:

numControls = length(app.components)
display_names = cell(numControls, 1);
for k = 1 : numControls % Don't use i as an iterator.
    % Set the current value to the name of the component
    display_names{k} = app.components(k).name; % Use braces, not parentheses.
end