How do I efficiently edit GUIDE item handles in a loop?

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Carlo Cavaliere Ballesta 2019-2-21

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https://ww2.mathworks.cn/matlabcentral/answers/446234-how-do-i-efficiently-edit-guide-item-handles-in-a-loop

关闭： MATLAB Answer Bot 2021-8-20

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I have a program written using GUIDE (yes, I still use it), and i'm trying to modify the properties a series of objects named Sector1, Sector 2... SectorN in a loop. The problem is, to do this I'm currently using eval (expression), such as:

expression = ['set(handles.Sector',num2str(i),',''Position'', pos1);'];
eval(expresion);  

But it runs terribly slow, as the recommendations here state. I'm wondering if there is a workaround to avoid using eval while still being able to call the objects in a loop. Thanks.

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Stephen23 2019-2-21

编辑：Stephen23 2019-2-21

"I'm wondering if there is a workaround to avoid using eval while still being able to call the objects in a loop"

Just access them directly in handles using dynamic fieldnames:

https://www.mathworks.com/help/matlab/matlab_prog/generate-field-names-from-variables.html

Remember that putting numbers into variable names is a sign that you are doing something wrong... as you are finding out, it forces you into writing slow, complex, buggy code that is hard to debug. Read this to know why:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Using indexing would be the most efficient solution and is what you should have used.

Personally I would also avoid GUIDE. Ultimately it is simpler to write your own code.

https://www.mathworks.com/matlabcentral/answers/419658-how-to-fix-this-erro-in-guide#comment_614333

Carlo Cavaliere Ballesta 2019-2-22