擅长:python、mysql、java
<p>将<a href="https://www.google.com/search?q=series+isin&rlz=1C1GCEU_enIN822IN823&oq=series+isin&aqs=chrome..69i57j0l5.2462j0j7&sourceid=chrome&ie=UTF-8" rel="nofollow noreferrer">^{<cd1>}</a>和<code>groupby()</code>与<code>sum</code>一起使用:</p>
<pre><code>dfA[dfA.IDCol2.isin(dfB.ColA)].groupby('IDCol1')['IDCol3'].sum().reset_index(name='Sum')
</code></pre>
<hr/>
<pre><code> IDCol1 Sum
0 ABC 8
1 CDE 9
</code></pre>