擅长:python、mysql、java
<p>下面是一种用<code>size</code>转换并乘以在<code>pointInTime</code>上取<code>pd.factorize</code>的结果的方法:</p>
<pre><code>df['cumCount'] = (df.groupby('pointInTime').ticketId
.transform('size')
.mul(pd.factorize(df.pointInTime)[0]+1))
pointInTime ticketId cumCount
0 2008-01-01 111 3
1 2008-01-01 222 3
2 2008-01-01 333 3
3 2008-01-07 444 6
4 2008-01-07 555 6
5 2008-01-07 666 6
6 2008-01-14 777 9
7 2008-01-14 888 9
8 2008-01-14 999 9
</code></pre>