topic Re: Create a parameter from flexible number of arguments in SAS Programming

Create a parameter from flexible number of arguments

Ronein — Tue, 31 Jul 2018 09:24:23 GMT

Hello

I cannot go to all process so I will ask the question from this step only.

%macro mmacro;
%do j=1 %to &k.;
&Xj.
%end;
%mend;

I want to create a parameter that get the value: X1,X2,X3,X4.........................

(As you can see the number of arguments are not fixed and depends on value of parameter &k.)

Re: Create a parameter from flexible number of arguments

Kurt_Bremser — Tue, 31 Jul 2018 09:31:31 GMT

Do it in a data step:

%let k=5;
data _null_;
length param $100;
do j = 1 to &k;
  param = catx(',',param,'X' !! strip(put(j,best.)));
end;
call symputx('param',param);
run;
%put param=&param.;

Re: Create a parameter from flexible number of arguments

Astounding — Tue, 31 Jul 2018 10:57:12 GMT

I'm not sure that this result would be useful. But you can get it easily enough:

%macro mmacro;

%local j;

%global mylist;

%let mylist=X1;
%do j=2 %to &k.;
%let mylist = &mylist,X&j.;
%end;
%mend;

************** EDITED:

Based on some of your earlier questions, it is possible you don't want X1,X2,X3, but rather the value of the macro variables instead of the names of the macro variables. While I agree with posters that have warned you that the commas are unnecessary in almost all cases and can cause trouble later, that's just something to keep in mind. Here is the variation that uses the values of a set of macro variables:

%macro mmacro;

%local j;

%global mylist;

%let mylist=&X1;
%do j=2 %to &k.;
%let mylist = &mylist,&&X&j.;
%end;
%mend;

Re: Create a parameter from flexible number of arguments

Patrick — Tue, 31 Jul 2018 11:01:37 GMT

@Ronein

With a macro you could use the parmbuff option as documented here:

http://support.sas.com/documentation/cdl//en/mcrolref/69726/HTML/default/viewer.htm#p1nypovnwon4uyn159rst8pgzqrl.htm

This option is rarely used and I can't really recommend to take such an approach. Anyway: Here a code sample:

%macro printz/parmbuff;
   %let num=1;
   %let dsname=%scan(&syspbuff,&num,%str(%(, %)));
   %put &=dsname;
   %do %while(&dsname ne);
      proc print data=&dsname;
      run;
      %let num=%eval(&num+1);
      %let dsname=%scan(&syspbuff,&num,%str(%(, %)));
   %end;
%mend printz;
%printz(sashelp.class, sashelp.air)

Alternatively when using a macro just pass in the string of values to a normal parameter (a macro variable) and then parse this macro variable. Just don't use a comma as delimiter as this gets already used by the macro statement to delimit parameters so you only ask for complications using the same for your value list.

Here some sample code using a blank as delimiter:

%macro printz(ds);
   %let num=1;
   %let dsname=%scan(&ds,&num,%str( ));
   %put &=dsname;
   %do %while(&dsname ne);
      proc print data=&dsname;
      run;
      %let num=%eval(&num+1);
      %let dsname=%scan(&ds,&num,%str( ));
   %end;
%mend printz;
%printz(sashelp.class sashelp.air)