1:Unused import 

环境：Ubuntu 14.04  eclipse 3.8

eclipse环境下利用PyDev插件做开发的时候，输入：import re,左边会出现一个黄色的警告，属标放上去后会显示：Unused import re

原因如下：(ref:http://stackoverflow.com/questions/16394732/unused-wild-import-why)

That message just tells you that you are importing features from a module that you don‘t need, which means you should probably import just what you need. You shuld simply use from foobar import x, ywhere x and y are the elements you actually need.The syntax from foobar import * is more useful in the command-line interpreter when you don‘t want to think or type many more characters for little benefit. But in a real project, you should not use that syntax since if you use it, it will not be clear which feature from the module you are going to use.

也就是说：只import re 而没有使用 re，等后面使用到re的方法时候，这个警告自然会消除

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