擅长:python、mysql、java
<p>您正在原始函数中返回<code>rating</code>。。但是<code>rating</code>是<strong>行,而不是任何列的值</p>
<pre><code>>>> df
A B C Genre Title Year
0 7 6 \N g1 m1 y1
1 \N 5 7 g2 m2 y2
2 \N \N \N g3 m3 y3
3 \N 4 1 g4 m4 y4
4 \N \N 3 g5 m5 y5
>>> def rating(row):
if row['A'] != r'\N':
return row['A']
if row['B'] != r'\N':
return row['B']
if row['C'] != r'\N':
return row['C']
return 'Unrated'
>>> df['Rating'] = df.apply(rating, axis = 1)
>>> df
A B C Genre Title Year Rating
0 7 6 \N g1 m1 y1 7
1 \N 5 7 g2 m2 y2 5
2 \N \N \N g3 m3 y3 Unrated
3 \N 4 1 g4 m4 y4 4
4 \N \N 3 g5 m5 y5 3
</code></pre>