擅长:python、mysql、java
<p>将<code>pd.DataFrame.groupby</code>与<code>pd.DataFrame.cumsum</code>一起使用</p>
<pre><code>df1['cumsum'] = df1.groupby(['Month', 'Region'])['Value'].cumsum()
</code></pre>
<p>结果:</p>
<pre><code> Year Month Region Value cumsum
0 1978 1 South 1.0 1.0
1 1990 1 North 22.0 22.0
2 1990 2 South 33.0 33.0
3 1990 2 Mid W 12.0 12.0
4 1998 1 South 1.0 2.0
5 1998 1 North 12.0 34.0
6 1998 2 South 2.0 35.0
7 1998 3 South 4.0 4.0
8 1998 1 Mid W 2.0 2.0
</code></pre>