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Re: Convert list to another form but providing same information

Path csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From Mark Lawrence <breamoreboy@yahoo.co.uk>
Newsgroups comp.lang.python
Subject Re: Convert list to another form but providing same information
Date Mon, 21 Mar 2016 19:24:39 +0000
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On 21/03/2016 18:30, Maurice wrote:
> Just figured why:
>
> If I type this on the kernel:
>
> weirdList = [[0]*3]*5
>
> weirdList
> Out[257]: [[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
>
> weirdList[0][0] = 1
>
> weirdList
> Out[259]: [[1, 0, 0], [1, 0, 0], [1, 0, 0], [1, 0, 0], [1, 0, 0]]
>
> All first elements of the sublists also changes. I dunno why...
>

https://docs.python.org/3/faq/programming.html#why-did-changing-list-y-also-change-list-x

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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Thread

Convert list to another form but providing same information Maurice <mauricioliveiraguarda@gmail.com> - 2016-03-21 11:26 -0700
  Re: Convert list to another form but providing same information Maurice <mauricioliveiraguarda@gmail.com> - 2016-03-21 11:30 -0700
    Re: Convert list to another form but providing same information Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-21 19:24 +0000
    Re: Convert list to another form but providing same information anantguptadbl@gmail.com - 2016-03-22 07:23 -0700
  Re: Convert list to another form but providing same information Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-21 19:21 +0000
  Re: Convert list to another form but providing same information Peter Otten <__peter__@web.de> - 2016-03-21 20:22 +0100
  Re: Convert list to another form but providing same information Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-03-21 20:03 +0000
    Re: Convert list to another form but providing same information Ian Kelly <ian.g.kelly@gmail.com> - 2016-03-21 14:12 -0600
      Re: Convert list to another form but providing same information Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-03-22 00:31 +0000
        Re: Convert list to another form but providing same information Chris Angelico <rosuav@gmail.com> - 2016-03-22 11:58 +1100
        Re: Convert list to another form but providing same information Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-03-22 15:34 +1100
    Re: Convert list to another form but providing same information Ian Kelly <ian.g.kelly@gmail.com> - 2016-03-21 14:14 -0600
  Re: Convert list to another form but providing same information Steven D'Aprano <steve@pearwood.info> - 2016-03-22 11:13 +1100
  Re: Convert list to another form but providing same information Paul Rubin <no.email@nospam.invalid> - 2016-03-21 18:35 -0700
    Re: Convert list to another form but providing same information Steven D'Aprano <steve@pearwood.info> - 2016-03-22 21:49 +1100

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