topic Re: How to implement a macro function inside a data step in SAS Programming

How to implement a macro function inside a data step

smeet — Fri, 23 Sep 2022 21:24:47 GMT

Hello. I'd like to run a macro function over every observation of a variable in a dataset. My code (which doesn't work) looks like this:

DATA _NULL_;
	SET Work.HAVE;
	%MacroFunction(Var1);
RUN;

where %MacroFunction is a macro defined earlier in my code that takes one argument. This %MacroFunction creates an external .txt file for each entry under Var1.

Running just %MacroFunction(Observation1) in open code works perfectly, but since I'd like to run this for every observation under Var1, I'd prefer not to write %MacroFunction(Observation1), %MacroFunction(Observation2), etc., especially when the number of observations may change with each run.

Re: How to implement a macro function inside a data step

PaigeMiller — Fri, 23 Sep 2022 21:30:09 GMT

It would help if you showed us the macro function eponymously named %MacroFunction

In general, putting a macro function inside a data step requires there to be valid, legal, working SAS data step syntax when the macro function executes and generates text.

So this simple example won't work:

%macro macrofunction;
proc means data=sashelp.class; run;
%mend;

data abc;
    set sashelp.class;
    new_variable=%macrofunction;
run;

Why? Because you cannot embed PROC MEANS inside a SAS data step code, this is not valid working legal SAS data step code.

At this link, I provide a macro that does work inside a data step, because it generates valid working legal data step code. https://communities.sas.com/t5/SAS-Programming/How-to-Calculate-Death-Rates-in-One-Statement-in-a-DATA-step/m-p/834522#M329930

Why does it work? Because the macro resolves to legal valid working SAS data step code, when the value of &string is C the code becomes sum_c + (cause=:"C"); and this is valid in a data step.

Re: How to implement a macro function inside a data step

Quentin — Fri, 23 Sep 2022 21:56:12 GMT

It's hard to know without seeing your macro, but it sounds like you are trying to use a dataset to "drive" macro calls.

One approach to this is using DOSUBL or CALL EXECUTE. This thread has some examples: https://communities.sas.com/t5/SAS-Programming/Iteratively-pass-each-row-of-a-data-file-to-a-macro/m-p/814988

Re: How to implement a macro function inside a data step

Reeza — Fri, 23 Sep 2022 21:58:41 GMT

You may want either CALL EXECUTE or PROC FCMP instead, depends on the code as stated by others.

Re: How to implement a macro function inside a data step

Tom — Fri, 23 Sep 2022 22:25:22 GMT

The is not such thing as a macro "function".

The closest thing would be a function style macro that generates only part of a SAS statement so that you could call it in the middle of a SAS statement.

And the way you are calling the macro you couldn't use such a function style macro anyway since your code would only work if the macro generates one or more complete STATEMENTS. But only statements that could be part of a data step. Such as assignment statements or IF THEN statement or perhaps LABEL or FORMAT statements.