擅长:python、mysql、java
<p>如果顺序不重要-使用集合:</p>
<pre><code>a = [['Rostock', 'Lubeck'], ['Rostock', 'Hamburg'], ['Rostock', 'Bremen'], ['Rostock', 'Hannover']]
print list(set(y for x in a for y in x)) # prints ['Rostock', 'Hannover', 'Bremen', 'Lubeck', 'Hamburg']
</code></pre>