擅长:python、mysql、java
<p>您也可以尝试<code>pd.crosstab()</code></p>
<pre><code>Group Size
Short Small
Short Small
Moderate Medium
Moderate Small
Tall Large
pd.crosstab(df.Group,df.Size)
Size Large Medium Small
Group
Moderate 0 1 1
Short 0 0 2
Tall 1 0 0
</code></pre>
<p>编辑:为了让你出局</p>
<pre><code>pd.crosstab(df.Group,df.Size).replace(0,np.nan).\
stack().reset_index().rename(columns={0:'Time'})
Out[591]:
Group Size Time
0 Moderate Medium 1.0
1 Moderate Small 1.0
2 Short Small 2.0
3 Tall Large 1.0
</code></pre>