topic Re: How to create dynamic suffix variable name and assign it to macro ? in SAS Programming

How to create dynamic suffix variable name and assign it to macro ?

Forecaster — Tue, 20 Dec 2016 01:44:46 GMT

I'm trying to create a variable list to pass it to a function. Right now I'm creating it manually for instance if n = 5, I have to create x1,x2,x3,x4,x5 seperated by comma, if n = 6 then I have to create x1,x2,x3,x4,x5,x6

%let n = 5;

%let variable = x1,x2,x3,x4,x5;

%let n=6;

%let variable = x1,x2,x3,x4,x5,x6;

my question is how to create "variable" macro automatically depening on the n value specified?

Re: How to create dynamic suffix variable name and assign it to macro ?

Shmuel — Tue, 20 Dec 2016 01:56:51 GMT

run next lines under a macro:

%let n=5;

%let varables=;

%do i=1 %to &n;

%let variables = &variables.x&i ;

%if i < &n %then %let vaiables = &variables,;

%end;

%put VAEIABLES= &variables;

Re: How to create dynamic suffix variable name and assign it to macro ?

Jagadishkatam — Tue, 20 Dec 2016 02:00:46 GMT

%let n=5;
%let variable=x;

data have;
do i=1 to &n;
variable=cats("&variable",put(i,best.));
output;
end;
run;

proc sql noprint;
select variable into :varlist separated by ',' from have;
quit;

%put &varlist;

Re: How to create dynamic suffix variable name and assign it to macro ?

Patrick — Tue, 20 Dec 2016 02:07:37 GMT

The solution will depend a bit on how you actually get to this value of 'n' but the way you've asked the question you could go for a function style macro.

%macro create_list(basename,n);
  %local _var;
  %if &n>0 %then %let _var=&basename.1;
  %do i=2 %to &n;
    %let _var=&_var,&basename&i;
  %end;
  &_var
%mend;

%let variable=%create_list(x,6);

%put &=variable;

Re: How to create dynamic suffix variable name and assign it to macro ?

Forecaster — Tue, 20 Dec 2016 02:27:29 GMT

impressive

Re: How to create dynamic suffix variable name and assign it to macro ?

RW9 — Tue, 20 Dec 2016 09:50:21 GMT

"pass it to a function" - in what sense do you need a macro or macro variable for this task. Base SAS - the programming language - provides numerous different avenues to achieve these results without resorting to %$%% code:

Arrays:

array x{6};

List of paramters:

sum(of x:);

List between paratmers:

keep=x1--x6;

Etc.

Re: How to create dynamic suffix variable name and assign it to macro ?

Forecaster — Tue, 20 Dec 2016 13:30:56 GMT

@RW9I'm trying to pass the macro into a FMCP function which would be later used in an optimization procedure. For example: The key here is the when defining function fdef, lets suppose I have x1,x2,x3,x4,x5,x6. none of them work except hard coding. If there is a better way to pass the &var please let me know

proc fcmp outlib=sasuser.myfuncs.mypkg;

   function fdef(&var);
   array x[&n.];
   array y[&n.,&n.] /nosym (&mat.); 

	fx = 0;
 	do j = 1 to dim(y);
		fx = fx + (y[i,j]- (x[i]*x[j]));
      	
	end;
	return(fx);
   endsub;

Re: How to create dynamic suffix variable name and assign it to macro ?

RW9 — Tue, 20 Dec 2016 13:37:19 GMT

Seems to me like your trying to use every technology other than Base SAS. Your given fuction can be copied into a datastep, no need to hide code behind a compiled function. Your macro variables can be replaced with variable lists and arrays or ideally remodelling your data into a better normalised structure so that by groups can be utilised. Also, as it looks like your are doing lots of calculations across arrays, perhaps proc iml may be the way to go.

Anyways just opinion of course.