擅长:python、mysql、java
<p>您可以连接,然后像现在这样对代码进行分组,然后转换:</p>
<pre><code>In [9]: df["out"] = (
(df["code"] + "_" + df["type"] + "_" + df["note"]).groupby(df["code"]).transform("first"))
In [10]: df
Out[10]:
pid code type note out
0 1 A M alvedon A_M_alvedon
1 1 B D pain B_D_pain
2 1 C M ulcer C_M_ulcer
3 2 A M ipren A_M_alvedon
4 2 B D hurt B_D_pain
5 3 A M alvedon A_M_alvedon
6 3 B D hurt B_D_pain
7 3 C M stomach C_M_ulcer
8 4 A M ipren A_M_alvedon
9 4 B D pain B_D_pain
10 5 A M ipren A_M_alvedon
11 5 B D pain B_D_pain
</code></pre>