Python 常量与变量

先在lib文件夹中定义一个模块

 class _const(object):
     class ConstError(TypeError):pass

     def __setattr__(self, name, value):
         if self.__dict__.has_key(name):
             raise self.ConstError,"Cant't rebind const(%s)" % name
         self.__dict__[name]=value

     def __delattr__(self, name):
         if name in self.__dict__:
             raise self.ConstError,"Cant't unbind const(%s)" % name
         raise NameError,name

 import sys
 sys.modules[__name__]=_const()

然后新建文件，赋值，那么定义的const.value则是一个常量

import constconst.value=5print const.value

2.变量

i=5print ii+=1print ii+=2print ii+=3print i