擅长:python、mysql、java
<p>不要使用sum(),它在加入列表时很慢。在</p>
<p>相反,<a href="http://docs.python.org/tutorial/datastructures.html#nested-list-comprehensions" rel="noreferrer">nested list comprehension</a>将起作用:</p>
<pre><code>>>> x = [['A', 'B', 'C'], ['D', 'E', 'F'], ['G', 'H', 'I']]
>>> [elem for sublist in x for elem in sublist]
['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I']
>>> ['<tr>' + elem + '</tr>' for elem in _]
</code></pre>
<p>使用<a href="http://docs.python.org/library/itertools.html#itertools.chain" rel="noreferrer">itertools.chain</a>的建议也很好。在</p>