擅长:python、mysql、java
<p>你可以使用groupby。将对年份栏和面包栏的前4个字符进行分组,如下所示:</p>
<pre><code>df.groupby([df['Year'].str[:4], 'Bread']).sum()
Out:
Amount
Year Bread
2008 brown 120
white 110
2009 brown 120
golden 3000
</code></pre>
<p>或作为常规列:</p>
<pre><code>df.groupby([df['Year'].str[:4], 'Bread'], as_index=False).sum()
Out:
Bread Amount
0 brown 120
1 white 110
2 brown 120
3 golden 3000
</code></pre>