擅长:python、mysql、java
<p>尝试:</p>
<pre class="lang-py prettyprint-override"><code>y = datetime.datetime(2015, 5, 12).strftime('%d-%m-%Y')
df2.loc[:, 'new'] = df1.loc[df1['date'] == y, "age"].item()
# Output
a b new
0 1 4 27
1 2 5 27
2 3 6 27
</code></pre>