I wouldn't code it with a macro - if all you want to do is subtract something from the variables, use an array. BUT, to answer the specific question, you need extra &'s to resolve the whole macro variable, so, &&predname&j (and sometimes a third, though I've not had much success recognizing when it is one or the other except by trial & error).

The way to do that coding properly: data datar00; infile "c:\&filenamer00"; input &predname1 &predname2 random; array preds &predname1 &predname2; *and if you have many vars, there are lots of ways to automatically pick them, such as using _NUMERIC_ or the colon (wildcard); do _n_ =1 to dim(preds); preds[_n_] = preds[_n_] - constant; end; run;

-Joe

On Fri, Jul 31, 2009 at 2:02 PM, Tonidandel, Scott < sctonidandel@davidson.edu> wrote:

> I am stumped and could use some assistance resolving the following problem. > This is all part of a much larger code but my problem is located within the > following data step. I am trying to us a DO-loop to subtract a constant from > some variables that are globally referenced using %let. > > %let predname1=TMA; > %let predname2=TSL; > %let numpred=2; > > data datar00; > infile "C:\&filenamer00"; > input &predname1 &predname2 random; > %macro test; > %do j = 1 %to &numpred; > &predname&j=&predname&j-constant; > %end; > %mend; > %test; > run; > > > The macro executes if written as follows: > %macro test; > %do j = 1 %to &numpred; > &predname1=&predname1-constant; > %end; > %mend; > > As it will iterate twice for &predname1. > But, I can't seem to combine the global variable &predname with &j. When I > try that as in the first code, I get: > WARNING: Apparent symbolic reference PREDNAME not resolved. > > This is probably something obvious as I am not an experienced SAS > programmer but I swear I have stared at it for hours and can't figure out > why it won't work. Any help would be appreciated. Thanks in advance. > > Scott T >