topic Re: macro looping in SAS Programming

macro looping

newbie — Sun, 02 Oct 2011 16:47:40 GMT

In th below code as you can see im trying to create a macro variable for each iteration of 'i' but when i try to print them onto saslog im getting the error

as Apparent symbolic reference ST1not resolved .

Any help would be appreciated!

%macro do(m,n);

%let i=;

data _null_;

%do i=&m %to &n;

st=%eval(&i+1);

call symput("st&i",st);

%put &&st&i;

%end;

run;

%mend;

%do(1,2)

macro looping

art297 — Sun, 02 Oct 2011 17:10:23 GMT

I can't test your code at the moment, but I doubt if it will work for a couple of reasons: (1) I think %do is a reserved word and (2) the macro variable won't resolve within the same datastep it is created. Try something like the following:

%macro doit(m,n);

%do i=&m %to &n;

data _null_;

st=%eval(&i+1);

call symput("st&i",st);

run;

%put &&st&i;

%end;

%mend;

%doit(1,2)

macro looping

Re: macro looping

Tom — Sun, 02 Oct 2011 17:22:19 GMT

You are mixing up macro logic and data step logic. The reason that the %PUT is getting an error is that it is compiled BEFORE the data step runs. So the CALL SYMPUT function has not been called yet.

In a macro use the %LET statement to assign a value to a macro variable.

%macro doit(m,n);
  %do i=&m %to &n;
    %let st&i=%eval(&i+1);
  %end;
%mend doit;
%doit(1,2);

In a data step use the DO statement to loop.

%let m=1;
%let n=2;
data _null_;
  do i=&m to &n;
    call symputx(cats('ST',i),i+1);
  end;
run;

PS: Do not use DO as the name of a macro as %DO is already a macro statement.