擅长:python、mysql、java
<p>使用缺失列的<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.set_index.html" rel="nofollow noreferrer">^{<cd1>}</a>:</p>
<pre><code>df = df.set_index('query').groupby('Id')['count'].nlargest(2).reset_index()
print (df)
Id query count
0 001 ccd 100
1 001 bcd 30
2 002 ahhd 30
3 002 ahe 28
</code></pre>