擅长:python、mysql、java
<p>在我看来,更好的方法是在使用<code>groupby.size</code>之前删除重复项:</p>
<pre><code>res = df.drop_duplicates()\
.groupby('Site_Where_Served').size()\
.reset_index(name='Site_Visit_Count')
print(res)
Site_Where_Served Site_Visit_Count
0 hospital 3
1 inpatient 1
</code></pre>