11-20-2015 11:13 AM - edited 11-20-2015 11:13 AM
The reverse() function ...
If your variable is numeric convert it to character first using PUT(var, 8.)
11-20-2015 11:30 AM
If you would like something a bit more obscure and not subject to the issues of one id= 123 and another 321 in your data try the various bitwise logical functions if your ID is numeric.
For example look at
data _null_; do x= 10 to 1010 by 10 ; y = bnot(x); z = bnot(y); put y= z= ; end; run;