擅长:python、mysql、java
<p><strong>选项1</strong><br/>
<code>fillna</code></p>
<pre><code>df2 = df2.replace('non', np.nan)
df2.set_index('PAUCode').SubClass\
.fillna(df1.set_index('PAUCode').SubClass)
PAUCode
2 RB
2 RB
2 RB
3 CZ
1 RA
2 RB
3 CZ
Name: SubClass, dtype: object
</code></pre>
<hr/>
<p><strong>选项2</strong><br/>
<code>map</code></p>
<pre><code>df2.PAUCode.map(df1.set_index('PAUCode').SubClass)
0 RB
1 RB
2 RB
3 CZ
4 RA
5 RB
6 CZ
Name: PAUCode, dtype: object
</code></pre>
<hr/>
<p><strong>选项3</strong><br/>
<code>merge</code></p>
<pre><code>df2[['PAUCode']].merge(df1, on='PAUCode')
PAUCode SubClass
0 2 RB
1 2 RB
2 2 RB
3 2 RB
4 3 CZ
5 3 CZ
6 1 RA
</code></pre>
<p>注意这里数据的顺序改变了,但是答案保持不变。你知道吗</p>