擅长:python、mysql、java
<p>我想您应该使用<code>df2</code>作为联接的左侧。您可以使用<code>pd.DateOffset</code>添加14天</p>
<pre><code># create dataset with specific date and specific date + 14
df2_14 = df2.set_index('state')['date'].apply(pd.DateOffset(14)).reset_index()
df = pd.concat([df2, df2_14])
# now join the values from df1
df = df.join(df1.set_index(['state', 'date']),
how='left',
on=['state', 'specificDate'])
</code></pre>