擅长:python、mysql、java
<p>你可以用<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.groupby.html" rel="nofollow">^{<cd1>}</a>乘以4。<code>Multiindex</code>(<code>python</code>从<code>0</code>开始,所以<code>level=3</code>):</p>
<pre><code>summed = df.groupby(level=3).sum()
</code></pre>