擅长:python、mysql、java
<p>使用<code>with</code>上下文管理器,不要使用<a href="http://docs.python.org/2/library/stdtypes.html#file.readlines" rel="nofollow">readlines()</a>,因为它会将文件的全部内容读入列表中。相反,逐行迭代<a href="http://docs.python.org/2/library/stdtypes.html#file-objects" rel="nofollow">file object</a>并查看是否存在特定的单词;如果存在-则写入输出文件:</p>
<pre><code>with open("/tmp/LostShots/LostShots.txt", "r") as input_file, \
open('results.txt', 'w') as output_file:
for line in input_file:
if "Lost" in line:
output_file.write(line)
</code></pre>
<p>请注意,对于python<;2.7,<code>with</code>中不能有多个项:</p>
^{pr2}$