擅长:python、mysql、java
<p>我觉得这更具可读性:</p>
<pre><code>a = [['Rostock', 'Lubeck'], ['Rostock', 'Hamburg'], ['Rostock', 'Bremen'], ['Rostock', 'Hannover']]
result = []
for x in a:
for y in x:
if y not in result:
result.append(y)
</code></pre>
<p>这是输出:</p>
<pre><code>>>> print(result)
['Rostock', 'Lubeck', 'Hamburg', 'Bremen', 'Hannover']
</code></pre>