topic Re: How to create macro variable and use it in one data set in SAS Programming

How to create macro variable and use it in one data set

Lee_wan — Wed, 01 Jul 2020 06:27:12 GMT

Hi all,

How to modify the code to run successfully?

I want to use &faa in one data set.

%scan(symget('faa'),&i,|) can't run successfully too.

%macro ff;
data a;
  if _n_=1 then do; 
     aa='f|dd|ff';
     call symputx('faa',aa);
  end;
  set xx;
  %let i=1;
  %do %until (%scan(&faa,&i,|) = );
     %scan(&f,&i,|)='1';
     %let i=%eval(&i+1);
  %end;
run;

%mend;
%ff;

Thanks.

Re: How to create macro variable and use it in one data set

Patrick — Wed, 01 Jul 2020 06:33:13 GMT

Anything macro executes before the SAS data step and that's why you've got a timing issue here. The macro %do loop executes before the SAS data step creates macro variable &faa.

Please explain what you're actually trying to do. There is a good chance that you don't need macro code at all.

Re: How to create macro variable and use it in one data set

andreas_lds — Wed, 01 Jul 2020 06:37:42 GMT

What do you want to achieve? It seems as if you want to to set the variable "f", "dd" and "ff to 1. All variables seem to be alphanumeric, right? If yes, you don't need macro-code, but an array:

data a;
   set xx;

   array vars[3] f dd ff;

   do i = 1 to dim(vars);
      vars[i] = '1';
   end;

   drop i;
run;

Re: How to create macro variable and use it in one data set

Kurt_Bremser — Wed, 01 Jul 2020 06:41:21 GMT

You have a basic macro timing problem. CALL SYMPUTX works at data step execution time, but the macro code is resolved while the macro creates the code that will later be compiled into a data step, so it will try to fetch the macro variable long before it is created.

The deeper issue here is that you try to abuse the macro language for something it is not meant to do: manipulate data.

To keep values across observations, use a RETAINed variable, or set a macro variable before the data step. To present valid code, we first need to know the data you start with, and what you want to get out of it.

Please supply an example dataset in a data step with datalines, and the expected result from it.

Re: How to create macro variable and use it in one data set

ChrisNZ — Wed, 01 Jul 2020 07:13:26 GMT

Timing issue as you were told.

When the data step compiles, all variables must be known.

So:

%scan(&faa,&i,|)

must be resolved.

This is of course impossible in your scenario as &f is unknown at compile time.

Also note the inconsistency: you seem to have confused variables &f and &faa .

Re: How to create macro variable and use it in one data set

Lee_wan — Wed, 01 Jul 2020 07:50:15 GMT

Thanks a lot.

I put the step of creating macro variable before this data set.

But I have a new question.

why I use double quotation marks in hash then the log generates issue?

When I replace them with single quotes('cmseq'), there's no problem.

Re: How to create macro variable and use it in one data set

ChrisNZ — Wed, 01 Jul 2020 07:54:09 GMT

Your double quotes are curly quotes and not typed from the keyboard. Use straight quotes. Type them yourself in the SAS editor.

Re: How to create macro variable and use it in one data set

Lee_wan — Wed, 01 Jul 2020 08:09:57 GMT

data cm;
    if _N_=1 then do;
        dcl hash h(multidata:'Y');
        h.definekey('usubjid', "cmseq");
        h.definedata('qnam', 'qval');
        h.definedone();

        do until(eof);
          set sdtm.suppcm end=eof;
          cmseq=input(idvarval,best.);
          rc=h.add();
        end;
    end;

It's not about double quotes.