Check edit text box validity for "i" and "j" characters

Hello,

I have in my GUI an edit text item where the user has to enter only numbers. I check this with the following command:

isnan(str2double(get(hObject, 'String')))

However, when you input i or j, this condition is not satisfied. What is the trick to solve this issue?

Answer 1

[Walter Roberson]

There is nothing to solve. i and j are number-forming characters in MATLAB, just like d and e and '+' and '-' and '.' are.

If you wanted to test for only digits rather than for number then you would use a different test. For example, you could use ismember()

[Matt]

Thank you, I will do that!

Answer 2

[Stephen23]

Rather than converting to numeric, simply check that the string contains only digits. This is easy using the inbuilt function isstrprop:

>> all(isstrprop('123', 'digit')) 
ans = 1
>> all(isstrprop('123i', 'digit')) 
ans = 0

Note that you need to decide what constitutes a "number", as i and j could be considered to be numbers, just like e or π. What about + and -?