Python __setitem__()、__getitem__()、__delitem__()

class A(object):  
    def __init__(self):  
        self[‘B‘] = "BB"  
        self[‘D‘] = "DD"  
        del self[‘D‘]  
      
    def __setitem__(self,name,value):  
        ‘‘‘‘‘ 
        @summary: 每当属性被赋值的时候都会调用该方法，因此不能再该方法内赋值 self.name = value 会死循环 
        ‘‘‘  
        print "__setitem__:Set %s Value %s"%(name,value)  
        self.__dict__[name] = value  
      
    def __getitem__(self,name):  
        ‘‘‘‘‘  
        @summary: 当访问不存在的属性时会调用该方法 
        ‘‘‘  
        print "__getitem__:No attribute named ‘%s‘"%name  
        return None  
      
    def __delitem__(self,name):  
        ‘‘‘‘‘  
        @summary: 当删除属性时调用该方法 
        ‘‘‘  
        print "__delitem__:Delect attribute ‘%s‘"%name  
        del self.__dict__[name]  
        print self.__dict__  
      
      
if __name__ == "__main__":  
    X = A()  
    b = X[‘bb‘]