topic How to assign Macro Variable Depends on Another MVar Value?! in SAS Programming

How to assign Macro Variable Depends on Another MVar Value?!

hellohere — Wed, 22 Oct 2025 07:06:31 GMT

I know how to assign MVar like below.

%let ref_mm_ind=100; %let ref_mm_ind_stind=%sysfunc(max(10,%eval(&ref_mm_ind.-150*4)));

Now I have another macro variable, mmnote, which can be max or min.

Now I need if mmnote=max, assign 400 to ref_mm_ind_stind; if mmnote=min, keep untouch

as above.

How to do with just %let lines?!

Thanks,

Re: How to assign Macro Variable Depends on Another MVar Value?!

FreelanceReinh — Wed, 22 Oct 2025 07:31:48 GMT

Hello @hellohere,

You can use the IFN and IFC functions in conjunction with %SYSFUNC to assign a value conditionally:

%let ref_mm_ind_stind=%sysfunc(ifn(&mmnote=max, 400, &ref_mm_ind_stind));

Re: How to assign Macro Variable Depends on Another MVar Value?!

hellohere — Wed, 22 Oct 2025 07:39:01 GMT

Thanks,

Re: How to assign Macro Variable Depends on Another MVar Value?!

ballardw — Thu, 23 Oct 2025 05:30:02 GMT

Related functions WHICHN and WHICHC may be useful if you need to extend this logic to selecting more choices.

Be very sure of the CASE of the compared character values using IFC and WHICHC.

%let ref_mm_ind_stind=%sysfunc(ifn(&mmnote=max, 400, &ref_mm_ind_stind)); would not get the desired behavior if &mmnote has a value of MAX (or many others with one or more capital letters). If the resolved values of the macro variable MMNOTE might have case issues then use one of the %LOWCASE or %UPCASE in macro code such as

%let ref_mm_ind_stind=%sysfunc(ifn(%lowcase(&mmnote)=max, 400, &ref_mm_ind_stind));

This can be very important if you have to deal with user entered values such as a response to a prompt.

Re: How to assign Macro Variable Depends on Another MVar Value?!

Tom — Thu, 23 Oct 2025 13:17:03 GMT

Note sure why you think it makes sense to limit to "just %let lines".

So assuming that mmnote is also a macro variable then to test if its value is min you would add a simple %IF/%THEN/%DO block.

%let mmnote=max;
%let ref_mm_ind=100;
%if &mmnote=max %then %do;
  %let ref_mm_ind_stind=400;
%end;
%else %do;
  %let ref_mm_ind_stind=%sysfunc(max(10,%eval(&ref_mm_ind.-150*4)));
%end;

So no need to build complex nested function calls that will be difficult to maintain.

Also do you really want to calculate the formula (&ref_mm_ind - 150*4) using the INTEGER ONLY arithmetic that the macro function %EVAL() uses? That will only work if REF_MM_IND only includes digits. If you remove the %EVAL() then the formula will be passed to SAS itself to handle so that normal arithmetic will be used instead.