Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #29861

Re: List Problem

References <5126348a-8e87-493d-975c-d6273e59784c@googlegroups.com> <b6555e91-54ba-42fb-bd99-561cb971c2ce@googlegroups.com>
Date 2012-09-24 07:57 +1000
Subject Re: List Problem
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.1157.1348437456.27098.python-list@python.org> (permalink)

Show all headers | View raw

On Mon, Sep 24, 2012 at 7:44 AM, jimbo1qaz <jimmyli1528@gmail.com> wrote:
> On Sunday, September 23, 2012 2:31:48 PM UTC-7, jimbo1qaz wrote:
>> I have a nested list. Whenever I make a copy of the list, changes in one affect the other, even when I use list(orig) or even copy the sublists one by one. I have to manually copy each cell over for it to work.
>>
>> Link to broken code: http://jimbopy.pastebay.net/1090401
>
> No, actually that's the OK code. http://jimbopy.pastebay.net/1090494 is the broken one.

The first thing I'd change about that code is the whole thing of using
try/exec/except to suppress IndexError. Definitely not good code. I'm
not wholly certain, but I think you might run into weird issues with
negative OOBounds indices (since Python treats a negative list index
as counting from the far end).

This is nothing to do with your originally requested issue, which I
can't see the cause of in your script there. But when you assign a
list, you just get another reference to the same list.

ChrisA

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

List Problem jimbo1qaz <jimmyli1528@gmail.com> - 2012-09-23 14:31 -0700
  Re: List Problem jimbo1qaz <jimmyli1528@gmail.com> - 2012-09-23 14:44 -0700
    Re: List Problem Chris Angelico <rosuav@gmail.com> - 2012-09-24 07:57 +1000
    Re: List Problem Dave Angel <d@davea.name> - 2012-09-23 18:03 -0400
    Re: List Problem Chris Angelico <rosuav@gmail.com> - 2012-09-24 08:27 +1000
      Re: List Problem Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-23 22:37 +0000
        Re: List Problem Chris Angelico <rosuav@gmail.com> - 2012-09-24 08:45 +1000
    Re: List Problem Chris Angelico <rosuav@gmail.com> - 2012-09-24 08:30 +1000
    Re: List Problem "Littlefield, Tyler" <tyler@tysdomain.com> - 2012-09-23 18:56 -0600
    Re: List Problem Chris Angelico <rosuav@gmail.com> - 2012-09-24 11:52 +1000
  Re: List Problem Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-23 22:07 +0000
  Re: List Problem jimbo1qaz <jimmyli1528@gmail.com> - 2012-09-23 15:44 -0700

csiph-web