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Using Switch/Case to assign values
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Poseidon
le 20 Avr 2023
Commenté : Cris LaPierre
le 20 Avr 2023
Hi
I am trying to use switch/case like below but when I run it, says eq is unrecognised variable or function. This is for an app.
switch app.SelectEvaporatorTypeDropDown.Value
case 'Forced Circlation (pumped)'
eq(1)=1;
case 'Falling Film'
eq(1)=2;
case 'Agitated Film (scraped wall)'
eq(1)=3;
case 'Short Tube'
eq(1)=4;
case 'Long Tube'
eq(1)=5
end
3 commentaires
DGM
le 20 Avr 2023
I don't see any way that the given code would ever produce that specific error. While eq() is a builtin function, and it's probably a bad idea to be naming your variables after functions, it's not apparent to me how that would be causing this specific error either.
Of course, you didn't include the entire error message backtrace, so it's not clear that this chunk of code is even part of the problem.
Fangjun Jiang
le 20 Avr 2023
Although not recommended, your code does not have error here.
- "eq" is a function. use some other variable name, e.g. Myeq
- Before this code, pre-allocate the variable and value, Myeq=1;
app.SelectEvaporatorTypeDropDown.Value='Forced Circlation (pumped)';
switch app.SelectEvaporatorTypeDropDown.Value
case 'Forced Circlation (pumped)'
eq(1)=1
case 'Falling Film'
eq(1)=2;
case 'Agitated Film (scraped wall)'
eq(1)=3;
case 'Short Tube'
eq(1)=4;
case 'Long Tube'
eq(1)=5
end
Réponse acceptée
Cris LaPierre
le 20 Avr 2023
Modifié(e) : Cris LaPierre
le 20 Avr 2023
I suspect the error is not occuring in the lines of code you have shared, but later on in another function when you try to use eq. Keep in mind variable scope. All your code in an app is inside functions. Once that function completes, its workspace is cleared.
If you want to share data between functions in your app, you must add the variable as a property of the app. See here: https://www.mathworks.com/help/matlab/creating_guis/share-data-across-callbacks-in-app-designer.html
You then access it by prepending with the property name with your app object name, like so: app.eq
4 commentaires
Cris LaPierre
le 20 Avr 2023
Just an additional note that you can also preallocate your property this way:
properties (Access = private)
Myeq = zeros(1,4); % Description
end
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