擅长:python、mysql、java
<p>理解你的问题有点困难。这个答案是回应你对@Sina Shabani的评论。如果希望一次仅获取一列的此信息,请使用:</p>
<pre><code> col_val_i_want = 'cat1' # Define what you want
mask = df['column-3'].eq(col_val_i_want) # Create a filter
df[mask].groupby('date').count() # Group by and get the count
</code></pre>