to which command refers ~isempty() to?

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!

Answer 1

[Cedric]

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.

Answer 2

[Walter Roberson]

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.

[Manuel Olschner]

that explains it very well, thank you!

[Jan]

@Cedric and Walter: I appreciate your clear explanations of this basic question.