Given the SAS data set SASUSER.HIGHWAY:
Steering Seatbelt Speed Status Count
——– ——– —– ——- —–
absent No 0-29 serious 31
absent No 0-29 not 1419
absent No 30-49 serious 191
absent no 30-49 not 2004
absent no 50+ serious 216
The following SAS program is submitted:
%macro SPLIT;
proc sort
data=SASUSER.HIGHWAY
out=WORK.UNIQUES(keep=Status)
nodupkey;
by Status;
run;
data _null_;
set uniques end=Lastobs;
macro variable reference completes
the program to create the WORK.NOT and
WORK.SERIOUS data sets?
A.
&Status&i
B.
&&Status&i
C.
&Status&Count
D.
&&Status&Count
答案:B。
我的问题是&&status这里为什么是两个&. 我认为&status就是refer宏。。?求解答