擅长:python、mysql、java
<p>当使用apply to a groupby时,我遇到了<code>.apply</code>将返回分组列。文档中有一个注释(<a href="http://pandas.pydata.org/pandas-docs/stable/groupby.html" rel="nofollow noreferrer">pandas.pydata.org/pandas-docs/stable/groupby.html</a>):</p>
<blockquote>
<p>"...Thus the grouped columns(s) may be included in the output as well as set the indices."</p>
</blockquote>
<p><code>.aggregate</code>将不返回分组列。</p>