clear all
mkf index
frame index{
        cntrade 000300, index
        keep date rmt
        gen year = year(date)
}   
出现结果：
do "/var/folders/hp/yp2s16gn001bjkq_z7mvrycm0000gn/T//SD01115.000000"

. clear all

. mkf index

. frame index{
.         hktrade 000300, index

option index not allowed
r(198);
.         keep date rmt
.         gen year = year(date)
. }   
r(198);

end of do-file

r(198);