擅长:python、mysql、java
<pre><code>df.insert(3,'B+C', df['B']+df['C'])
3 is the index
df.head()
A B C B+C D
0 1 2 2 4 1
1 1 1 2 3 1
2 3 1 0 1 1
3 2 4 4 8 4
</code></pre>
<p>之后你可以按照@yatu的步骤</p>
<pre><code>df['B+C'].ne(df['D'])
0 True
1 True
2 False
3 True dtype: bool
df['B+C'].ne(df['D']).sum()
3
</code></pre>