If the design of your code means that you're happy to allow a null result from your sub-string function, consider using SUBSTRN. This function provides the same essential functionality as SUBSTR but will not issue a NOTE message if it returns a null result. The two DATA steps below show the contrast in results:
15 data _null_;
16 MyString = 'Shorty';
17 a = substr(MyString,1,10);
18 b = substr(MyString,15,10);
19 put a= b= ;
20 run;
NOTE: Invalid third argument to function SUBSTR at line 17 column 8.
NOTE: Invalid second argument to function SUBSTR at line 18 column 7.
a=Shorty b=
MyString=Shorty a=Shorty b= _ERROR_=1 _N_=1
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
21
22 data _null_;
23 MyString = 'Shorty';
24 an = substrN(MyString,1,10);
25 bn = substrN(MyString,15,10);
26 put an= bn=;
27 run;
an=Shorty bn= Notice in particular how the attempt to assign a value to B where the starting position is beyond the length of the string produces _ERROR_ set to 1.
In the right situation, SUBSTRN can be very handy.
