NOTFIRST Function

Searches a character string for an invalid first character in a SAS variable name under VALIDVARNAME=V7, and returns the first position at which that character is found.

Category:	Character
Restriction:	I18N Level 2 functions are designed for use with SBCS, DBCS, and MBCS (UTF8).

Syntax

NOTFIRST(string <,start> )

Required Argument

string

is the character constant, variable, or expression to search.

Optional Argument

start

is an optional numeric constant, variable, or expression with an integer value that specifies the position at which the search should start and the direction in which to search.

Details

The NOTFIRST function does not depend on the TRANTAB, ENCODING, or LOCALE system options.

The NOTFIRST function searches a string for the first occurrence of any character that is not valid as the first character in a SAS variable name under VALIDVARNAME=V7. These characters are any except the underscore (_) and uppercase or lowercase English letters. If such a character is found, NOTFIRST returns the position in the string of that character. If no such character is found, NOTFIRST returns a value of 0.

If you use only one argument, NOTFIRST begins the search at the beginning of the string. If you use two arguments, the absolute value of the second argument, start, specifies the position at which to begin the search. The direction in which to search is determined in the following way:

If the value of start is positive, the search proceeds to the right.
If the value of start is negative, the search proceeds to the left.
If the value of start is less than the negative length of the string, the search begins at the end of the string.

NOTFIRST returns a value of zero when one of the following is true:

The character that you are searching for is not found.
The value of start is greater than the length of the string.
The value of start = 0.

Comparisons

The NOTFIRST function searches a string for the first occurrence of any character that is not valid as the first character in a SAS variable name under VALIDVARNAME=V7. The ANYFIRST function searches a string for the first occurrence of any character that is valid as the first character in a SAS variable name under VALIDVARNAME=V7.

Example

The following example uses the NOTFIRST function to search a string for any character that is not valid as the first character in a SAS variable name under VALIDVARNAME=V7.

data _null_;    
   string='Next = _n_ + 12E3;';  
   j=0;  
   do until(j=0);  
      j=notfirst(string,j+1);  
      if j=0 then put +3 "That's all";  
      else do;          
         c=substr(string,j,1);  
         put +3 j= c=;  
      end; 
   end;
run;

The following lines are written to the SAS log:

   j=5 c= 
   j=6 c==
   j=7 c= 
   j=11 c= 
   j=12 c=+
   j=13 c= 
   j=14 c=1
   j=15 c=2
   j=17 c=3
   j=18 c=;
   That's all