擅长:python、mysql、java
<p>您可以使用<a href="https://pandas.pydata.org/pandas-docs/stable/user_guide/groupby.html#transformation" rel="nofollow noreferrer">^{<cd1>}</a>和<code>max</code>这样做:</p>
<pre><code>df.loc[df['c'].eq(df.groupby('a')['c'].transform('max')), :]
a b c
0 x1 y1 9
1 x1 y2 9
4 x2 y5 10
8 x3 y9 8
9 x4 y10 11
10 x4 y11 11
11 x4 y12 11
</code></pre>