data test;
input name $20.;
cards;
zhang
san
san

li
si

wang
wu
;
run;

data test1;
    length name $20 fullname $100;
    do until (missing(name) or last);
           set test end=last;
           fullname=catx(" ",fullname,name);
        end;
        drop name;
run;

data demo;
input name $20.;
cards;
zhang
san

li
si

wang
wu

liu
xi
xi
;
run;


data want  (keep=tmp rename=(tmp=name)) ;
   length tmp  $ 20;
   retain tmp;
   set demo end=last ;
   tmp=catx('',tmp,name);
   if missing(name) or last then  do;
   output ;
   call missing(tmp);
   end;   
run;

循环中用set语句是不是不大好呢？性能会低一些？

请指教！