Best way to check if a character is alpha or numeric?

Ryan · November 21, 2015 at 5:49 AM

If I do

Code

if val(mystring) > 0
string is numeric

This works for numbers 1-9 but not 0.

How would I write a function that returns 'string is numeric' for '0' but 'string is not numeric for 'A'?

I suppose I could do:

Code

if val(mystring) > 0


or


if val(mystring) = 0
and mystring = "0"
string is numeric


else
string is not numeric

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but that's a bit complicated. Any better ideas?

PBarwick · November 21, 2015 at 6:36 AM

Does 'greater than or equal to' (>=) not work?

Popcorn · November 21, 2015 at 12:34 PM

Hey, I think your methods works fine, but even easier would be to use the Edit Object's Is text a number condition. Of course, if you're not using input text, you'll first have to add it to the Edit Object.

Ryan · November 22, 2015 at 5:07 AM

Quote

Does 'greater than or equal to' (>=) not work?

Unfortunately val(string) returns 0 for an alpha character, so >= would identify 'A' as being equal to 0 and '0' as being equal to zero, therefore concluding all strings are a number, just equal to 0.

I ended up using my method, but thanks for the info Popcorn, I didn't know Edit Object could do that.

schrodinger · November 22, 2015 at 11:41 AM

Another pretty quick way could be:

Lower$("my_string" ) = Upper$("my_string" )
>>> is numeric

Lower$("my_string" ) <> Upper$("my_string" )
>>> is text

won't work for special characters though...

yours is probably quickest+most solid way,
along with the editbox as Popcorn suggested

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