data a;
input ticker $ date mmddyy10. price;
format date mmddyy10.;
cards;
ABC   1/1/2002  10
ABC   1/2/2002  11
ABC   1/5/2002  12
ABC   1/6/2002  13
ABC   1/7/2002  14
DEF   1/1/2002  9
DEF   1/2/2002  11
DEF   1/5/2002  13
DEF   1/6/2002  15
DEF   1/7/2002  18
;
run;
data a1;
set a;
by ticker date;
if first.ticker=1 then seq=1;
else seq+1;
run;
%let l=1;
data a2;
do i=1 to n;
set a1 point=i nobs=n;
if (seq le &l.) then do;
return=.;
output;
end;
else  do;
return=price/lag&l.(price)-1;
output;
end;
end;
stop;
run;
想要以ticker和date排序，得到同样的ticker下price/lag&l.(price)-1的值，但是结果不对。数据是论坛里的。多谢了！