to which command refers ~isempty() to?

Question

Manuel Olschner 2013-10-14

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评论： Jan 2013-10-14

Sorry for the dumb question, but I am working on a matlab code I didn't write myself and several '~isempty(<1xn> cell in here)' are occuring. Since I am relatively new to matlab and programming, I just don't understand yet to what the isempty refers. I couldn't find any satisfying answers and so i thought maybe i could find help here. The isempty is always bound to an if loop.

like:

 set (handles. ...
 set (handles. ...
 if ~isempty(ZoneElementProtNameUnder{1,1})
        set(handles.protUnder,'String',ZoneElementProtNameUnder{1,1});
 else ...

So does isempty work with the 'set handles' or with the 'ZoneElement...', or even with a previous command? Or what exactly is it doing?

I appreciate any answers or help, thanks!

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Answer 1

Cedric 2013-10-14

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https://ww2.mathworks.cn/matlabcentral/answers/90160-to-which-command-refers-isempty-to#answer_99600

编辑：Cedric 2013-10-14

在 MATLAB Online 中打开

ZoneElementProtNameUnder is a 2D cell array. ZoneElementProtNameUnder{1,1} is the content of cell on column 1 and row 1 (curly brackets = "content of" for cell arrays). As cells can have empty content, the condition in the IF statement

if ~isempty(ZoneElementProtNameUnder{1,1})

is just checking that this cell's content is not empty. If true, then the expression

set(handles.protUnder,'String',ZoneElementProtNameUnder{1,1});

is using the content.

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Answer 2

Walter Roberson 2013-10-14

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In that code, ZoneElementProtNameUnder is a cell array that has at least one element. To access just that one element unwrapped from the cell array, you would code ZoneElementProtNameUnder{1,1} . If the entity that is stored there is empty, then isempty(ZoneElementProtNameUnder{1,1}) would be true, and ~isempty(ZoneElementProtNameUnder{1,1}) would be false; contrawise if ZoneElementProtNameUnder{1,1} had something in it, then isempty(ZoneElementProtNameUnder{1,1}) would be false and ~isempty(ZoneElementProtNameUnder{1,1}) would be true.