/* Macro to convert all uppercase variables in SAS data file to lowercase.
Useful before converting a SAS file to Stata files */

%macro convert_vars_lowcase(upcsfile); 
     %let datafile=%sysfunc(open(&upcsfile)); 
     %let nr_vars=%sysfunc(attrn(&datafile,nvars)); 
     %put &nr_vars;
     data &upcsfile; 
           set &upcsfile(rename=(%do i = 1 %to &nr_vars; 
        /*function of varname returns the name of a SAS data set variable*/
        %let var&i=%sysfunc(varname(&datafile,&i));
        &&var&i=%sysfunc(lowcase(&&var&i)) /*rename all variables*/ 
        %end;)); 
        %let close=%sysfunc(close(&datafile)); 
  run; 
%mend convert_vars_lowcase;