>>George,
>>
>>IsDigit() checks only first symbol, so it's not suitable for my situation. Type() works fine.
>>
>>Example:
>>
>>myNumber='12345'
>>type(myNumber)='N'
>>isDigit(myNumber)=.t.
>>
>>myNumber='1hffhhf'
>>type(myNumber)='U'
>>isdigit(myNumber)=.t.
>
>This behavior is not in accordance with the docs. Whether or not it's a bug, I don't know. The TYPE() function, according to the documentation, should receive a character expression, not a variable. If this behavior is a bug, in may be corrected in a future service pack or release. If this does happen, it may cause problems for you in the future.

It will accept a variable whose value is of the type character, and then judge its contents. That's why the first example returned N (variable myNumber was a string containing numeric expression) and the other U (it contained an undecidable expression).

>While ISDIGIT() does only check the first character in a multi character string, there's nothing to keep you from looping through and using it to check each character via SUBSTR() like this:

>llisnumber = .T.
>lni = 1
>DO WHILE llisnumber AND (lni <= LEN(mystring))
>  llisnumber = ISDIGIT(SUBSTR(mystring, lni, 1))
>  lni = lni + 1
>ENDDO
>RETURN llisnumber

Or, better, you can use StrFilter() from, ahem, Foxtools :)

lcJustDigits=strfilter(myNumber, '0123456789.+-')
if lcJustDigits=myNumber
* it's really a number
else ... well, maybe not.