擅长:python、mysql、java
<p>使用<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.drop_duplicates.html" rel="nofollow noreferrer">^{<cd1>}</a>仅获取<code>image</code>的唯一<code>map</code>值:</p>
<pre><code>#default keep first dupe
s = df2.drop_duplicates('image').set_index('image')['id']
df1['newids'] = df1['image'].map(s)
#keep last dupe
s = df2.drop_duplicates('image', keep='last').set_index('image')['id']
df1['newids'] = df1['image'].map(s)
#keep last dupe
d = dict(zip(df2['image'], df2['id']))
df1['newids'] = df1['image'].map(d)
</code></pre>