<p>我相信你需要:</p>
<pre><code>df['defadd'] = df['caseno'].map(def_dict).fillna('')
print (df)
caseno defname defadd
0 123 defendant1 [123address, 123address2, 123csz]
1 456 defendant2 [456address, 456address2, 456csz]
2 789 defendant3
3 000 defendant4
</code></pre>
<p>或:</p>
<pre><code>df['defadd'] = df['caseno'].map(lambda x: def_dict.get(x, ''))
print (df)
caseno defname defadd
0 123 defendant1 [123address, 123address2, 123csz]
1 456 defendant2 [456address, 456address2, 456csz]
2 789 defendant3
3 000 defendant4
</code></pre>
<p>对于缺少的列表:</p>
<pre><code>df['defadd'] = df['caseno'].map(lambda x: def_dict.get(x, []))
print (df)
caseno defname defadd
0 123 defendant1 [123address, 123address2, 123csz]
1 456 defendant2 [456address, 456address2, 456csz]
2 789 defendant3 []
3 000 defendant4 []
</code></pre>