擅长:python、mysql、java
<p>IIUC,使用<code>groupby</code>和<code>cumcount</code>累计计算唯一值。那么,就<code>reindex</code></p>
<pre><code>df.drop_duplicates(['user', 'prod'])\
.groupby('user')['prod']\
.cumcount()\
.add(1)\
.reindex(df.index)\
.ffill()
</code></pre>
<hr/>
<pre><code> user time prod uniq_sbe
0 a 1.0 k 1.0
1 a 1.1 k 1.0
2 b 1.2 t 1.0
3 a 1.2 t 2.0
4 b 1.3 y 2.0
5 a 1.3 z 3.0
6 b 1.3 x 3.0
</code></pre>