This useful addition came in SAS 9.2 and I am amazed that it isn’t enabled by default. To do that you need to set the MINOPERATOR option unless someone has done it for you in the SAS AUTOEXEC or another configuration program. Thus, the safety first approach is have code like the following:
options minoperator;
%macro inop(x);
%if &x in (a b c) %then %do;
%put Value is included;
%end;
%else %do;
%put Value not included;
%end;
%mend inop;
%inop(a);
Also, the default delimiter is the space so if you need to change that, then the MINDELIMTER option needs setting. Adjusting the above code so that the delimiter now is the comma character gives us the following:
options minoperator mindelimiter=”,”;
%macro inop(x);
%if &x in (a,b,c) %then %do;
%put Value is included;
%end;
%else %do;
%put Value not included;
%end;
%mend inop;
%inop(a);
Without any of the above, the only approach is to have the following and that is what we had to do for SAS versions prior to 9.2:
%macro inop(x);
%if &x=a or &x=b or &x=c %then %do;
%put Value is included;
%end;
%else %do;
%put Value not included;
%end;
%mend inop;
%inop(a);
It may be clunky but it does work and remains a fallback in newer versions of SAS. Saying that, having the IN operator available makes writing SAS Macro code that little bit swisher so it’s a good thing to know.