topic Macro do loop help in SAS Programming

Macro do loop help

EC27556 — Wed, 25 Nov 2020 15:00:50 GMT

Hi, instead of writing all the below out for 100 variables I would like to simplify it with a macro do loop. However, I am unsure of how I would do this as I need not only the value of 'i' but the value of 'i'+1 in each iteration of the do loop to make it work. How would I resolve this issue - see in the macro I am trying to write below, I have left question marks where I am unsure how to write a variable that I essentially want to resolve as x(&i.+1). is there any way of actually writing this do loop so I can simplify the x1=x2 x2=x3 etc.?

data want;

set have;

rename x1=x2 x2=x3 x3=x4 x4=x5.....x99=x100;

run;

%macro abc;

data want;

set have;

rename %do i=1 %to 99; x&i.=x????? %end;;

run;

mend;

%abc;

Re: Macro do loop help

ballardw — Wed, 25 Nov 2020 15:26:51 GMT

Major error: missing % for %mend statement. If you have actually run that code the SAS session is likely unstable.

%macro abc;
data want;
   set have;
   rename 
    %do i=1 %to 99; 
       x&i.=x%eval(&i+1)
    %end;
   ; 
run;
%mend;

Please post code in a code box opened on the forum with either the </> or "running man" icon.

Note the indentation to tell where the macro do loop starts and ends a bit easier than all on one line and that the semicolon that ends the Rename is also more visible to that purpose.

If the sole purpose of code is to rename variables then you should do it that with Proc Datasets. A data step like this has to process every observation and for large data sets code be quite time consuming. Proc datasets will do this in place.

Proc datasets library=work;
   modify have;
   rename x1=x2
          x2=x3
          <repeat>
   ;
run;
quit;

Re: Macro do loop help

EC27556 — Wed, 25 Nov 2020 19:01:44 GMT

Fab, thank you, works great 🙂