擅长:python、mysql、java
<pre><code>lrdata3.groupby('year')['total_vehicles'].sum().to_frame()
</code></pre>
<p>或<a href="https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.core.groupby.GroupBy.transform.html" rel="nofollow noreferrer">groupby and transform</a></p>
<pre><code>lrdata3['yearlytotal_vehicles']=lrdata3.groupby('year')['total_vehicles'].transform('sum')
</code></pre>