擅长:python、mysql、java
<p>您应该合并在groupby+mean之后创建的数据帧,因为行数不完全匹配:</p>
<pre><code>df = pd.DataFrame({'Animal': ['Falcon', 'Falcon', 'Parrot', 'Parrot'], 'Max Speed': [380., 370., 24., 26.]})
print(df)
means = df.groupby(['Animal'])['Max Speed'].mean()
print(means)
df = pd.merge(df, means, on='Animal', how='left')
print(df)
</code></pre>