单例模式和迭代器模式

单例模式在Python中可以查看这里

借用里面一段话，说的相当明白：

I don't really see the need, as a module with functions (and not a class) would serve well as a singleton. All its variables would be bound to the module, which could not be instantiated repeatedly anyways.

If you do wish to use a class, there is no way of creating private classes or private constructors in python, so you can't protect against multiple instantiations, other than just via convention in use of your API. I would still just put methods in a module, and consider the module as the singleton.

如果想看单例，下边链接是c#的单例介绍

http://terrylee.cnblogs.com/archive/2005/12/09/293509.html

个人觉得没有比这里的单例介绍更透彻的了。

 

迭代器模式是Python内置支持的模式，一般不用自己写，具体可以查看这里