Syntax Issue in If Statement Using Handles

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Jay
Jay 2016-4-11
评论： Jay 2016-4-11
I am trying to write an if statement in a function, to determine if the handles values are of valid type, as per the stipulation in the texts written above said handles in the GUI.
For handle 'edit1' I have written:
if handles.edit1 == NaN
set(handles.edtit2, 'enable', 'off') && set(handles.listbox1, 'string', 'Date must be of stated syntax')
else set(handles.edit2, 'enable', 'on')
end
During runtime the code skips to else not flagging
if handles.edit1 == Nan
as true thus setting the 'handles.edit2' off and having the error showing in listbox1.
What is wrong with my if statement?

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采纳的回答

Stephen23
Stephen23 2016-4-11
编辑：Stephen23 2016-4-11
You cannot test for equality of NaN's, because as the documentation clearly states, NaN's are not equal to each other. Use isnan instead:
>> handles.edit1 = NaN;
>> handles.edit1 == NaN
ans =
0
>> isnan(handles.edit1)
ans =
1

更多回答（1 个）

Walter Roberson
Walter Roberson 2016-4-11
Use ishghandle() instead testing for NaN .

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