擅长:python、mysql、java
<p>当id上有<a href="https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.groupby.html" rel="nofollow noreferrer">groupby</a>和<a href="https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.sum.html" rel="nofollow noreferrer">sum</a>时,可以使用<a href="http://pandas.pydata.org/pandas-docs/version/0.19.1/generated/pandas.DataFrame.merge.html" rel="nofollow noreferrer">merge</a>:</p>
<pre><code>pd.merge(df,df.groupby("id").sum().reset_index(), on='id',how='outer')
</code></pre>
<p>输出</p>
<p><a href="https://i.stack.imgur.com/HcqQB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HcqQB.png" alt="enter image description here"/></a></p>