Mar 20, 2011

SAS Macro to add a prefix to some or all variables in a data set...

Often we need to add a prefix to some or all variables in a dataset before we might have to merge datasets that have similar column attributes…This macro would allow you to do that….
Try it for yourself….
SAS Macro to add a prefix to some or all variables in a data set...
to be used like this...
inpdsn - input dataset name libname.dsnname
prefix - prefix that you want to assign
outdsn - output dataset name libname.dsnname
excludevars - vars that you do not want to rename with the prefix
%macro prefixvars(inpdsn,prefix,outdsn,excludevars=);  
/* split the excludevars into individual macro var names for later use*/
%let num=1;
%let excludevar=%scan(%upcase(&excludevars),&num,' ');
%let excludevar&num=&excludevar;
%do %while(&excludevar ne );
            %let num=%eval(&num + 1);
            %let excludevar=%scan(&excludevars,&num,' ');
            %let excludevar&num=&excludevar;
%let numkeyvars=%eval(&num - 1); /* this is number of variables given in the exclude vars */
 %let dsid=%sysfunc(open(&inpdsn));   /* open the dataset and get the handle */                                                                                                    
 %let numvars=%sysfunc(attrn(&dsid,nvars)); /* get the number of variables */                                                                                               
  data &outdsn;                                                                                                                           
   set &inpdsn(rename=(
   /*rename all the variables that are not in the excludevars= */                                                                                                                 
            %do i = 1 %to &numvars;
               %let flag=N;
               %let var&i=%sysfunc(varname(&dsid,&i)); 
               %do j=1 %to &numkeyvars;
               %if %upcase(&&var&i) eq &&excludevar&j %then %let flag=Y;                           
               %if &flag eq N %then %do; &&var&i=&prefix&&var&i  %end;
   %let rc=%sysfunc(close(&dsid));                                                                                                       
%mend prefixvars;                                                                                                                            
/*Call the macro now*/