i and j pass isnan test?

I have code which extracts data from a gui entry as follows:

handles.bonusI = get(handles.bonusEB,'string');
handles.bonusI = str2double(handles.bonusI);

if isnan(handles.bonusI) == 0
    Code executes
else
    error displays
end

For every character I have tested that are not numbers, an error will be displayed. Except i and j. When testing handles.bonus, I both hold the value of 0.0000 + 1.0000i. I have no idea why this is, anyone got a clue?

[Stephen23]

" I have no idea why this is, anyone got a clue?"

Because i and j both represent a perfectly valid number:

http://mathworld.wolfram.com/ImaginaryNumber.html

https://en.wikipedia.org/wiki/Imaginary_unit

Answer 1

[Image Analyst]

i and j, as strings in your edit text box, can be passed to str2double() as a special case, but other character strings can't unless the string is all numbers. See this demo:

>> str2double('i')
ans =
                          0 +                     1i
>> str2double('a')
ans =
   NaN