<pre><code>In [34]: df1['PRODUCED_VALUES_1'] = \
df1['TARGET_NAME'].map(df2.set_index('IMAGE_NAME')['VALUES_1']) \
.fillna('DROPPED')
In [35]: df1
Out[35]:
FOOBAR TARGET_NAME ix PRODUCED_VALUES_1
320 foo fishinghook 320 DROPPED
321 bar doorlock 321 h
322 foo penguin 322 h
323 bar ashtray 323 DROPPED
324 foo cat 324 h
325 bar elephant 325 DROPPED
326 foo cupcake 326 DROPPED
328 bar exercisebench 328 m
</code></pre>
<p>或一个类似于@Bharath shetty溶液的衬垫:</p>
<pre><code>In [26]: df1.merge(df2[['IMAGE_NAME','VALUES_1']].rename(columns={'IMAGE_NAME':'TARGET_NAME'}),
...: how='left') \
...: .fillna('DROPPED') \
...: .rename(columns=lambda c: 'PRODUCED_' + c if c=='VALUES_1' else c) \
...: .set_index(df1.index)
...:
Out[26]:
FOOBAR TARGET_NAME ix PRODUCED_VALUES_1
320 foo fishinghook 320 DROPPED
321 bar doorlock 321 h
322 foo penguin 322 h
323 bar ashtray 323 DROPPED
324 foo cat 324 h
325 bar elephant 325 DROPPED
326 foo cupcake 326 DROPPED
328 bar exercisebench 328 m
</code></pre>