请教Python中的变量定义

CODE:

#!/usr/bin/python
# Filename: class.py

class Person:
        '''Defination of class Person'''
        count=0        
       
        def __init__(self,name):
                '''defination of constructor'''
                self.name = name
                Person.count+=1
                print self.name,'is created'

        def __del__(self):
                '''defination of destructor.'''
                print 'says bye to %s' %self.name

                Person.count-=1               
                if Person.count==0:
                        print self.name,'is the last one.'
                       
        def howmuch(self):
                return Person.count
                       
        def sayhello(self):
                print 'hello,',self.name       

p = Person('edward')

CODE:

edward is created
says bye to edward
Exception exceptions.AttributeError: "'NoneType' object has no attribute 'count'" in <bound method Person.__del__ of <__main__.Person instance at 0xb7e96c4c>> ignored

CODE:

p = Person('edward')

CODE:

pedward = Person('edward')

QUOTE:

Starting with version 1.5, Python guarantees that globals whose name begins with a single underscore are deleted from their module before other globals are deleted;

QUOTE:

原帖由 limodou 于 2006-6-10 13:39 发表
什么意思？python就是这样的处理的呀。当del一个对象时并不是直接释放，而是对这个对象的引用计数减１。为０时释放。