擅长:python、mysql、java
<p>另一种方法是使用<a href="https://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.apply.html" rel="nofollow noreferrer">^{<cd1>}</a>函数:</p>
<pre><code># inside apply, we can filter values
df.groupby('g')['val'].apply(lambda x: x[x!= ''].count()).median()
Out[2]: 1.0
</code></pre>