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Date: Sun, 06 Apr 2014 00:25:57 -0700
From: Gary Herron <gary.herron@islandtraining.com>
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Subject: Re: Mutable objects inside tuples - good or bad?
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Xref: csiph.com comp.lang.python:69747

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.