擅长:python、mysql、java
<p>为掩码和传递给<a href="https://numpy.org/doc/stable/reference/generated/numpy.where.html" rel="nofollow noreferrer">^{<cd1>}</a>的每个组比较移位值和回补缺失值:</p>
<pre><code>mask = df.groupby('ID')['Feature'].apply(lambda x: x.shift().bfill()).eq(df['Feature'])
df['Change'] = np.where(mask, 'no_change', 'change')
print (df)
ID Feature Change
0 1 0 no_change
1 1 0 no_change
2 1 1 change
3 1 1 no_change
4 2 0 no_change
5 2 0 no_change
6 2 1 change
7 2 2 change
</code></pre>