擅长:python、mysql、java
<p>试试这个</p>
<pre><code>df2= pd.DataFrame.from_dict(domain_to_app,orient='index').unstack().reset_index()
result= pd.merge(df1,df2[df2[0].notnull()],left_on=['domain'],right_on=['level_1'])
result=result[['domain','username',0]].rename(columns={0:'app'})
print result
</code></pre>
<p>输出:</p>
^{pr2}$
<p>说明:</p>
<p>从字典中创建Dataframe,执行<code>pd.merge</code>,然后根据需要清理Dataframe。在</p>