擅长:python、mysql、java
<p>或者更容易阅读、更干净的方法:</p>
<pre><code>df2=df[df['Num']==1]
df2.loc[df2['A']=='wer','C']=5
df2.loc[df2['A']=='ffg','D']=7
</code></pre>
<p>或要跳过警告,请按索引执行:</p>
^{pr2}$
<p>两种情况:</p>
<pre><code>print(df2)
</code></pre>
<p>是:</p>
<pre><code> Num A B C D
0 1 wer NaN 5.0 NaN
1 1 df NaN NaN NaN
2 1 ffg NaN NaN 7.0
</code></pre>
<p>如果要将其放回实际数据帧:</p>
<pre><code>df[df['Num']==1]=df2
</code></pre>