先用空格填充。在SAS

我有一个简单的数据，看起来像这样

+----------+------+--------+
| cis_code | yymm | sector |
+----------+------+--------+
| CTAGBTH  | 1707 | BANK   |
| CTAGBTH  | 1706 |        |
| CTAGBTH  | 1705 |        |
| CTAGBTH  | 1703 |        |
| CTAGBTH  | 1702 | RETAIL |
| CTAGBTH  | 1701 |        |
| CTAGBTH  | 1612 |        |
| CTAGBTG  | 1703 |        |
| CTAGBTG  | 1702 | AGRI   |
| CTAGBTG  | 1701 |        |
| CTAGBTG  | 1612 | RETAIL |
| CTAGBET  | 1705 |        |
| CTAGBET  | 1510 | FSI    |
| CTAGBET  | 1504 |        |
+----------+------+--------+

+-----------+-------+---------+---------------+
| cis_code  | yymm  |  sector |  Sector_Group |
+-----------+-------+---------+---------------+
| CTAGBET   |  1705 |         |               |
| CTAGBET   |  1510 |  FSI    |  FSI          |
| CTAGBET   | 1504  |         |  FSI          |
| CTAGBTG   |  1703 |         |               |
| CTAGBTG   | 1702  | AGRI    |  AGRI         |
| CTAGBTG   |  1701 |         |  AGRI         |
| CTAGBTG   | 1612  | RETAIL  | RETAIL        |
| CTAGBTH   | 1707  | BANK    |  BANK         |
| CTAGBTH   |  1706 |         |  BANK         |
| CTAGBTH   | 1705  |  BANK   |               |
| CTAGBTH   | 1703  |  BANK   |               |
| CTAGBTH   | 1702  | RETAIL  | RETAIL        |
| CTAGBTH   |  1701 |         |  RETAIL       |
| CTAGBTH   |  1612 |         |  RETAIL       |
+-----------+-------+---------+---------------+

在这个问题中，我想创建一个新的变量sector_summary，其中空格应该用cid_代码中的更改替换为sector。我已经尝试使用first.yymm和first.sector，但不幸的是没有任何效果。我还尝试了一些if语句，但不确定if语句是否适用于所有条件。数据应该是这样的

+----------+------+--------+
| cis_code | yymm | sector |
+----------+------+--------+
| CTAGBTH  | 1707 | BANK   |
| CTAGBTH  | 1706 |        |
| CTAGBTH  | 1705 |        |
| CTAGBTH  | 1703 |        |
| CTAGBTH  | 1702 | RETAIL |
| CTAGBTH  | 1701 |        |
| CTAGBTH  | 1612 |        |
| CTAGBTG  | 1703 |        |
| CTAGBTG  | 1702 | AGRI   |
| CTAGBTG  | 1701 |        |
| CTAGBTG  | 1612 | RETAIL |
| CTAGBET  | 1705 |        |
| CTAGBET  | 1510 | FSI    |
| CTAGBET  | 1504 |        |
+----------+------+--------+

+-----------+-------+---------+---------------+
| cis_code  | yymm  |  sector |  Sector_Group |
+-----------+-------+---------+---------------+
| CTAGBET   |  1705 |         |               |
| CTAGBET   |  1510 |  FSI    |  FSI          |
| CTAGBET   | 1504  |         |  FSI          |
| CTAGBTG   |  1703 |         |               |
| CTAGBTG   | 1702  | AGRI    |  AGRI         |
| CTAGBTG   |  1701 |         |  AGRI         |
| CTAGBTG   | 1612  | RETAIL  | RETAIL        |
| CTAGBTH   | 1707  | BANK    |  BANK         |
| CTAGBTH   |  1706 |         |  BANK         |
| CTAGBTH   | 1705  |  BANK   |               |
| CTAGBTH   | 1703  |  BANK   |               |
| CTAGBTH   | 1702  | RETAIL  | RETAIL        |
| CTAGBTH   |  1701 |         |  RETAIL       |
| CTAGBTH   |  1612 |         |  RETAIL       |
+-----------+-------+---------+---------------+

因此，基本上，如果给定的yymm有一个空白扇区，那么该扇区组在随后的几个月内也将是空白的，直到并且除非有另一个扇区被替换，并且在接下来的几个月内，该扇区组将进一步存在。

---

请告诉我如何操作

您只需保留值即可。看起来您还需要对数据进行排序（或者使用

BY

语句中的

NOTSORTED

选项）

+----------+------+--------+
| cis_code | yymm | sector |
+----------+------+--------+
| CTAGBTH  | 1707 | BANK   |
| CTAGBTH  | 1706 |        |
| CTAGBTH  | 1705 |        |
| CTAGBTH  | 1703 |        |
| CTAGBTH  | 1702 | RETAIL |
| CTAGBTH  | 1701 |        |
| CTAGBTH  | 1612 |        |
| CTAGBTG  | 1703 |        |
| CTAGBTG  | 1702 | AGRI   |
| CTAGBTG  | 1701 |        |
| CTAGBTG  | 1612 | RETAIL |
| CTAGBET  | 1705 |        |
| CTAGBET  | 1510 | FSI    |
| CTAGBET  | 1504 |        |
+----------+------+--------+

+-----------+-------+---------+---------------+
| cis_code  | yymm  |  sector |  Sector_Group |
+-----------+-------+---------+---------------+
| CTAGBET   |  1705 |         |               |
| CTAGBET   |  1510 |  FSI    |  FSI          |
| CTAGBET   | 1504  |         |  FSI          |
| CTAGBTG   |  1703 |         |               |
| CTAGBTG   | 1702  | AGRI    |  AGRI         |
| CTAGBTG   |  1701 |         |  AGRI         |
| CTAGBTG   | 1612  | RETAIL  | RETAIL        |
| CTAGBTH   | 1707  | BANK    |  BANK         |
| CTAGBTH   |  1706 |         |  BANK         |
| CTAGBTH   | 1705  |  BANK   |               |
| CTAGBTH   | 1703  |  BANK   |               |
| CTAGBTH   | 1702  | RETAIL  | RETAIL        |
| CTAGBTH   |  1701 |         |  RETAIL       |
| CTAGBTH   |  1612 |         |  RETAIL       |
+-----------+-------+---------+---------------+