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 Answer**Answer: 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)。