topic more effecient codes for repetitive data steps in SAS Programming

more effecient codes for repetitive data steps

msxas90 — Wed, 07 Mar 2018 11:39:33 GMT

if index_year=1990 then &name.0=&name.1990;

Hi all,

I am a relatively new SAS user and currently working with longitudinal data. In order to shape my data I am running a number of repetitive commands daily. For example, I need to assign time point depending on the index year. If index year is 1990, then timepoint starts from 1990. I have many variables and 28 time points and this makes my codes are just so bulky. Do you have any suggestions how I can apply macros or loops to save space and writing time? Thank you.

%let name=_alcdep;
DATA db;
set db;

if index_year=1990 then &name.1=&name.1991;
if index_year=1990 then &name.2=&name.1992;
if index_year=1990 then &name.3=&name.1993;
if index_year=1990 then &name.4=&name.1994;
if index_year=1990 then &name.5=&name.1995;
...
if index_year=1991 then &name.0=&name.1991;
if index_year=1991 then &name.1=&name.1992;
if index_year=1991 then &name.2=&name.1993;
if index_year=1991 then &name.3=&name.1994;
if index_year=1991 then &name.4=&name.1995;
....

run;

Re: more effecient codes for repetitive data steps

LinusH — Wed, 07 Mar 2018 11:57:34 GMT

Making long tables will end you up in awkward programming situations, so avoid it whenever possible.

But for your case, wrap your code into a macro, and use a %do loop to assign the year to your variables dynamically.

Re: more effecient codes for repetitive data steps

Kurt_Bremser — Wed, 07 Mar 2018 12:07:50 GMT

Using arrays?

array names {0:5} &name.0-&name.5;
array oldnames {0:5} &name.1990-&name.1995;
if index_year=1990 then do i = 1 to 5;
  names{i} = oldnames{i};
end;

and I guess you could expand that logic even for your index_year values.

Edit: deleted a mis-typed character;

Re: more effecient codes for repetitive data steps

msxas90 — Wed, 07 Mar 2018 12:45:55 GMT

Thank you so much! this is exactly what I was looking for.