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Re: Question about Pass-by-object-reference?

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On Tuesday, July 22, 2014 3:04:09 PM UTC-4, fl wrote:
Hi, 
Excuse me. I find that the OP misses some info. I rewrite it again:

I learn Python function call on tutorial. There is a link on this subject. 
http://robertheaton.com/2014/02/09/pythons-pass-by-object-reference-as-explained-by-philip-k-dick/ 

Although it explains clearly, the figure makes me puzzled. 

""Python is different. As we know, in Python, "Object references are passed by 
value". 

A function receives a reference to (and will access) the same object in memory as used by the caller. However, it does not receive the box that the caller is
storing this object in; as in pass-by-value, the function provides its own box 
and creates a new variable for itself. Let's try appending again:"" 

On the figure, I understand the figure about append function. Here is the lines:

When I enter the command lines on my computer: 
>>> def append(list):
... 	list.append(1)
... 	
>>> list=[0]
>>> append(list)
>>> print(list)
[0, 1]



But I don't understand the reassign function result:

>>> def reassign(list):
... 	list=[0,1]
... 
>>> list=[0]
>>> reassign(list)
>>> print list
[0]

Questions:
1. From the tutorial explanation, both function append and reassign use 
pass-by-object-reference. Is it right?

2. The tutorial says: "The caller doesn't care if you reassign the function's 
box. Different boxes, same content." about the reassign function. I don't
understand "Different boxes, same content". It uses different boxes (I agree).
But the results are different for the caller ([0]) and the function reassign 
([0, 1]).


What is wrong with my understanding? 



Thanks a lot, 

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Question about Pass-by-object-reference? fl <rxjwg98@gmail.com> - 2014-07-22 12:04 -0700
  Re: Question about Pass-by-object-reference? Ned Batchelder <ned@nedbatchelder.com> - 2014-07-22 15:32 -0400
    Re: Question about Pass-by-object-reference? fl <rxjwg98@gmail.com> - 2014-07-22 12:54 -0700
  Re: Question about Pass-by-object-reference? fl <rxjwg98@gmail.com> - 2014-07-22 12:34 -0700
    Re: Question about Pass-by-object-reference? Peter Pearson <ppearson@nowhere.invalid> - 2014-07-22 20:35 +0000
      Re: Question about Pass-by-object-reference? emile <emile@fenx.com> - 2014-07-22 13:46 -0700
        Re: Question about Pass-by-object-reference? fl <rxjwg98@gmail.com> - 2014-07-22 15:17 -0700
          Re: Question about Pass-by-object-reference? Joel Goldstick <joel.goldstick@gmail.com> - 2014-07-22 18:26 -0400
          Re: Question about Pass-by-object-reference? emile <emile@fenx.com> - 2014-07-22 15:33 -0700
          Re: Question about Pass-by-object-reference? Jerry Hill <malaclypse2@gmail.com> - 2014-07-22 19:06 -0400
        Re: Question about Pass-by-object-reference? fl <rxjwg98@gmail.com> - 2014-07-22 15:31 -0700
          Re: Question about Pass-by-object-reference? emile <emile@fenx.com> - 2014-07-22 15:40 -0700
      Re: Question about Pass-by-object-reference? fl <rxjwg98@gmail.com> - 2014-07-22 16:00 -0700
        Re: Question about Pass-by-object-reference? emile <emile@fenx.com> - 2014-07-22 16:10 -0700
  Re: Question about Pass-by-object-reference? Terry Reedy <tjreedy@udel.edu> - 2014-07-22 20:27 -0400
    Re: Question about Pass-by-object-reference? fl <rxjwg98@gmail.com> - 2014-07-22 18:49 -0700
      Re: Question about Pass-by-object-reference? Ben Finney <ben+python@benfinney.id.au> - 2014-07-23 11:59 +1000
        Re: Question about Pass-by-object-reference? Steven D'Aprano <steve@pearwood.info> - 2014-07-23 05:35 +0000
          Re: Question about Pass-by-object-reference? Chris Angelico <rosuav@gmail.com> - 2014-07-23 16:07 +1000
          Re: Question about Pass-by-object-reference? Ben Finney <ben+python@benfinney.id.au> - 2014-07-23 16:25 +1000
          Re: Question about Pass-by-object-reference? Terry Reedy <tjreedy@udel.edu> - 2014-07-23 18:51 -0400
            Re: Question about Pass-by-object-reference? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-07-24 03:22 +0000
              Re: Question about Pass-by-object-reference? Steven D'Aprano <steve@pearwood.info> - 2014-07-24 05:05 +0000
    Re: Question about Pass-by-object-reference? Steven D'Aprano <steve@pearwood.info> - 2014-07-23 05:36 +0000
      Re: Question about Pass-by-object-reference? Terry Reedy <tjreedy@udel.edu> - 2014-07-23 18:32 -0400
    Re: Question about Pass-by-object-reference? alex23 <wuwei23@gmail.com> - 2014-07-25 15:20 +1000
  Re: Question about Pass-by-object-reference? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-07-23 01:56 +0000

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