"For in" loop equivalent in SAS 9.3

Question

I'm searching for a while an equivalent of the for in loop (like in Python or in R) in SAS 9.3 macro language. The DO loop seem's to be the solution but did't work exactly as I want. I founded a way to do it in a data step with a DO loop but it don't work with the macro language. For example, in a data step, this code is working :

DATA _NULL_;
  DO i = 1,3,5,9;
    PUT i;
  END;
RUN;

And then the log prompt as expected :

1
3
5
9

When I try to do the same with an %DO loop in a Macro, I have an error.

%MACRO test();
  %DO i = 1,2,4,9 ;
    %PUT i = &i;
  %END;
%MEND;

%test();

The log promp these messages :

ERROR: Expected %TO not found in %DO statement.
ERROR: A dummy macro will be compiled

I'm quite new in SAS and stackoverflow so I hope my question is no too stupid. It's so simple to do this in Python and R then it must have a simple way to do it in SAS.

Thank's for help - J. Muller

Answer 1

The closest I've ever come across to this pattern in SAS macro language is this:

%MACRO test();

%let j=1;
%let vals=1 2 4 9;
%do %while(%scan(&vals,&j) ne );
  %let i=%scan(&vals, &j);

  %put &i;

  %let j=%eval(&j+1);
%end;
%MEND;

%test();

(Warning: untested, as I no longer have a SAS installation I can test this out on.)