Python: difference between urllib and urllib2

做为一个Python菜鸟，以前一直懵懂于urllib和urllib2，觉得2是1的升级版。今天看到老外写的一篇《Python: difference between urllib and urllib2》才明白其中的区别。

 

You might be intrigued by the existence of two separate URL modules in Python -urllib and urllib2. Even more intriguing: they are not alternatives for each other. So what is the difference between urllib and urllib2, and do we need them both? 

 

你可能对于Python中两个独立存在的-urllib2和-urllib2感到好奇。更有趣的是：它们并非能够相互代替的。那么这两个模块间的区别是什么，而且这两个咱们都须要吗？

urllib and  urllib2are both Python modules that do URL request related stuff but offer different functionalities. Their two most significant differences are listed below: 

urllib 和urllib2都是接受URL请求的相关模块，可是提供了不一样的功能。两个最显著的不一样以下：

• urllib2 can accept a Request object to set the headers for a URL request,urllib accepts only a URL. That means, you cannot masquerade your User Agent string etc.

urllib2能够接受一个Request类的实例来设置URL请求的headers，urllib仅能够接受URL。这意味着，你不能够假装你的User Agent字符串等。

 

• urllib provides the urlencode method which is used for the generation of GET query strings, urllib2 doesn't have such a function. This is one of the reasons why urllib is often used along with urllib2.

urllib提供urlencode方法用来GET查询字符串的产生，而urllib2没有。这是为什么urllib常和urllib2一块儿使用的缘由。

For other differences between urllib and urllib2 refer to their documentations, the links are given in the References section.