Hi David.

>> Is there a quick way to determine if a character string represents a legal numeric string (contains only digits and maybe a sign or .)? <<

In addition to what the others have told you, you can use the FoxTools StrFilter function to do this like so:

SET LIBRARY TO HOME()+"FoxTools"
LOCAL lcString, lcResultString

lcResultString = StrFilter( lcString, "01234567+-." )
IF lcResultString == lcString
   *** The original string contains only legal characters
ENDIF

Marcia