Does EXIST work in GUIDE (GUI)

Question

Lex 2011-7-11

0
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https://ww2.mathworks.cn/matlabcentral/answers/11310-does-exist-work-in-guide-gui

Hello, I have a little problem with EXIST function. I'm having a button with some calculations in code but later in code there is modification button(that asignin to workspace some other values). I've tride simple IF function (if exist modified value in workspace then do something else). But It does not work

if exist('N1pg','var')==0 
....
else 
...
end
if(get(handles.radiobutton10,'Value'))== (get(handles.radiobutton10,'Max'))
N1pg=str2num(get(handles.edit86,'String'));
assignin('base','N1pg',N1pg);

Thank you for solution\fix.

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Answer 1

Jan 2011-7-11

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https://ww2.mathworks.cn/matlabcentral/answers/11310-does-exist-work-in-guide-gui#answer_15410

EXIST checks the existence in the workspace of the current function. ASSIGNIN('base', ...) assigns the variable in the base workspace. Therefore EXIST cannot see the variable.

Creating variables in another workspace is a frequent source of problems. It is more stable to create the variables locally in the GUI (see GUIDATA, UserData, ApplicationData) and use a dedicated function to export them on demand only.

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Answer 2

Paulo Silva 2011-7-11

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在 MATLAB Online 中打开

Inside your GUI or any function:

e=evalin('base','who'); %get all the variables names present in the workspace
if ismember('N1pg',e) %check if your variable is one of them
%is one of them, do something
else
%the variable isn't in the workspace yet, do something else    
end