Why doesnt decremental macro loop work?

[nravi]

Hi,

I am writing a %do loop with decreasing iterative value. But this doesn't work. Can anyone help?

%macro loop;

%do i=3 %to 1 by -1;

data b_&i.;

set a&i.;

run;

%end;

%mend;

%loop;

ERROR: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required. The condition was: 1 by -1

ERROR: The %TO value of the %DO I loop is invalid.

ERROR: The macro LOOP will stop executing.

[Reeza · Accepted solution]

Use %by rather than just by in your do loop statement.

%macro loop;

%do i=3 %to 1 %by -1;

data b_&i.;

set a&i.;

run;

%end;

%mend;

%loop;

[nravi]

That worked. Thank you