Re: Mutable objects inside tuples - good or bad?

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On 04/05/2014 11:53 PM, John Ladasky wrote:
> I find this programming pattern to be useful... but can it cause problems?
No.

What kind of problems are you considering?  It won't break Python. It's 
perfectly legal code.

The tuple c is still immutable, consisting of two specific objects, and 
(as always) without regard to the specifics or contents of those two 
objects.

Gary Herron

>
> Python 3.3.2+ (default, Feb 28 2014, 00:52:16)
> [GCC 4.8.1] on linux
> Type "help", "copyright", "credits" or "license" for more information.
>>>> a = [1,2,3]
>>>> b = [4,5,6]
>>>> c = (a,b)
>>>> c
> ([1, 2, 3], [4, 5, 6])
>>>> c[0][0] = 0
>>>> c
> ([0, 2, 3], [4, 5, 6])
>
> Comments appreciated.

Thread

Mutable objects inside tuples - good or bad? John Ladasky <john_ladasky@sbcglobal.net> - 2014-04-05 23:53 -0700
  Re: Mutable objects inside tuples - good or bad? Gary Herron <gary.herron@islandtraining.com> - 2014-04-06 00:25 -0700
  Re: Mutable objects inside tuples - good or bad? Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-04-06 00:55 -0700
    Re: Mutable objects inside tuples - good or bad? Rustom Mody <rustompmody@gmail.com> - 2014-04-06 08:07 -0700
  Re: Mutable objects inside tuples - good or bad? Chris Angelico <rosuav@gmail.com> - 2014-04-06 18:25 +1000
  Re: Mutable objects inside tuples - good or bad? Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-04-06 04:01 -0700
  Re: Mutable objects inside tuples - good or bad? Paul Kölle <paul@subsignal.org> - 2014-04-07 17:26 +0200
  Re: Mutable objects inside tuples - good or bad? Chris Angelico <rosuav@gmail.com> - 2014-04-08 01:44 +1000
  Re: Mutable objects inside tuples - good or bad? Paul Kölle <paul@subsignal.org> - 2014-04-07 21:46 +0200
  Re: Mutable objects inside tuples - good or bad? Chris Angelico <rosuav@gmail.com> - 2014-04-08 08:47 +1000
  Re: Mutable objects inside tuples - good or bad? Terry Reedy <tjreedy@udel.edu> - 2014-04-07 20:16 -0400
    Re: Mutable objects inside tuples - good or bad? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-04-08 02:53 +0000

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