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我有一個簡單的數據,看起來像這樣首先填充空白。在SAS
+----------+------+--------+
| 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 | |
+----------+------+--------+
在這個問題
我想創建一個新的變量sector_summary其中空白應該通過與cid_code變化的行業所取代。我曾嘗試使用first.yymm和first.sector,但不幸的是沒有任何工作。我也嘗試了一些if語句,但不確定if語句是否適用於所有條件。該數據應該是這樣的
+-----------+-------+---------+---------------+
| 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 |
+-----------+-------+---------+---------------+
所以基本上,如果沒有爲給定YYMM一個空白扇區的扇區羣也將是空白隨之而來的幾個月之前,除非有其被替換另一個部門,這將在接下來的幾個月裏會繼續在那裏。
請讓我知道如何去做