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Re: class object's attribute is also the instance's attribute?

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在 2012年8月30日星期四UTC+8下午7时54分35秒，Dave Angel写道：
> On 08/30/2012 06:55 AM, 陈伟 wrote:
> 
> > when i write code like this:
> 
> >
> 
> > class A(object):
> 
> >      
> 
> >     d = 'it is a doc.'
> 
> >     
> 
> >
> 
> > t = A()
> 
> >
> 
> > print t.__class__.d
> 
> > print t.d
> 
> >
> 
> > the output is same.
> 
> >
> 
> > so it means class object's attribute is also the instance's attribute. is it right? i can not understand it.
> 
> 
> 
> In your example, you have no instance attribute.  So when you use the
> 
> syntax to fetch one, the interpreter looks first at the instance,
> 
> doesn't find it, then looks in the class, and does.  That is documented
> 
> behavior.  Some people use it to provide a kind of default value for
> 
> instances, which can be useful if most instances need the same value,
> 
> but a few want to overrride it.
> 
> 
> 
> -- 
> 
> 
> 
> DaveA
thank you very much.

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class object's attribute is also the instance's attribute? 陈伟 <chenwei.address@gmail.com> - 2012-08-30 03:55 -0700
  Re: class object's attribute is also the instance's attribute? Dave Angel <d@davea.name> - 2012-08-30 07:53 -0400
    Re: class object's attribute is also the instance's attribute? 陈伟 <chenwei.address@gmail.com> - 2012-08-30 05:57 -0700
    Re: class object's attribute is also the instance's attribute? 陈伟 <chenwei.address@gmail.com> - 2012-08-30 05:57 -0700
  Re: class object's attribute is also the instance's attribute? Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2012-08-30 13:22 +0200
  Re: class object's attribute is also the instance's attribute? Marco Nawijn <nawijn@gmail.com> - 2012-08-30 05:34 -0700
    Re: class object's attribute is also the instance's attribute? Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2012-08-30 13:52 +0100
    Re: class object's attribute is also the instance's attribute? Hans Mulder <hansmu@xs4all.nl> - 2012-08-30 15:25 +0200
      Re: class object's attribute is also the instance's attribute? Marco Nawijn <nawijn@gmail.com> - 2012-08-30 07:11 -0700
        Re: class object's attribute is also the instance's attribute? Dave Angel <d@davea.name> - 2012-08-30 10:30 -0400
          Re: class object's attribute is also the instance's attribute? Marco Nawijn <nawijn@gmail.com> - 2012-08-30 07:48 -0700
            Re: class object's attribute is also the instance's attribute? Dave Angel <d@davea.name> - 2012-08-30 11:18 -0400
          Re: class object's attribute is also the instance's attribute? Marco Nawijn <nawijn@gmail.com> - 2012-08-30 07:48 -0700
            Re: class object's attribute is also the instance's attribute? Hans Mulder <hansmu@xs4all.nl> - 2012-08-30 17:20 +0200
              Re: class object's attribute is also the instance's attribute? Ben Finney <ben+python@benfinney.id.au> - 2012-08-31 09:58 +1000

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