Given the SAS data set WORK.ONE:
| X | Y | Z |
| 1 | A | 27 |
| 1 | A | 33 |
| 1 | B | 45 |
| 2 | A | 52 |
| 2 | B | 69 |
| 3 | B | 70 |
| 4 | A | 82 |
| 4 | C | 91 |
The following SAS program is submitted:
data WORK.TWO;
set WORK.ONE;
by X Y;
if First.Y;
run;
proc print data=WORK.TWO noobs;
run;
Which report is produced?
A.
| X | Y | Z |
| 1 | B | 45 |
| 2 | A | 52 |
| 2 | B | 69 |
| 3 | B | 70 |
| 4 | A | 82 |
| 4 | C | 91 |
B.
| X | Y | Z |
| 1 | A | 27 |
| 1 | B | 45 |
| 2 | A | 52 |
| 2 | B | 69 |
| 3 | B | 70 |
| 4 | A | 82 |
| 4 | C | 91 |
C.
| X | Y | Z |
| 1 | A | 33 |
| 1 | B | 45 |
| 2 | A | 52 |
| 2 | B | 69 |
| 3 | B | 70 |
| 4 | A | 82 |
| 4 | C | 91 |
D. The PRINT procedure fails because the data set WORK.TWO is not created in the DATA step.
Check AnswerAnswer: B
注解：将数据按X和Y分组，并将各个分组中的第一个观测值输入到WORK.TWO中。FIRST.variable的具体解释查看SAS Base (1)。