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Re: def __init__(self):

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On Tue, Apr 26, 2016 at 9:32 AM, Steven D'Aprano <steve@pearwood.info>
wrote:

> Subclassing immutable built-ins is the most obvious and simple (and
> probably
> common) way to get an immutable class. Actually immutable, short of doing
> wicked things with ctypes.
>

By wicked things with ctypes, do you mean something like this? By no means
do I suggest this actually be used by anybody for any reason.

Tested with '2.7.10 (default, Jul 14 2015, 19:46:27) \n[GCC 4.2.1
Compatible Apple LLVM 6.0 (clang-600.0.39)]'

import ctypes
def changeTuple(tuple, index, newValue):
    obj = ctypes.cast(id(tuple), ctypes.POINTER(ctypes.c_long))
    obj[3+index] = id(newValue)

>>> a = ('a','b','c')
>>> changeTuple(a, 0, 1)
>>> a
(1, 'b', 'c')
>>> changeTuple(a, 1, 3)
>>> a
(1, 3, 'c')

Chris

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Thread

def __init__(self): San <santanu01@gmail.com> - 2016-04-25 23:21 -0700
  Re: def __init__(self): Ben Finney <ben+python@benfinney.id.au> - 2016-04-26 16:31 +1000
  Re: def __init__(self): Gary Herron <gherron@digipen.edu> - 2016-04-26 00:06 -0700
  Re: def __init__(self): Ben Finney <ben+python@benfinney.id.au> - 2016-04-26 17:34 +1000
    Re: def __init__(self): Marko Rauhamaa <marko@pacujo.net> - 2016-04-26 11:25 +0300
      Re: def __init__(self): Steven D'Aprano <steve@pearwood.info> - 2016-04-27 02:12 +1000
        Re: def __init__(self): Random832 <random832@fastmail.com> - 2016-04-26 12:26 -0400
          Re: def __init__(self): Steven D'Aprano <steve@pearwood.info> - 2016-04-27 02:32 +1000
            Re: def __init__(self): Chris Kaynor <ckaynor@zindagigames.com> - 2016-04-26 09:59 -0700
              Re: def __init__(self): Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-04-27 14:54 +1000
            Re: def __init__(self): Chris Angelico <rosuav@gmail.com> - 2016-04-27 03:04 +1000
            Re: def __init__(self): Chris Kaynor <ckaynor@zindagigames.com> - 2016-04-26 10:13 -0700
            Re: def __init__(self): Ian Kelly <ian.g.kelly@gmail.com> - 2016-04-26 11:26 -0600
            Re: def __init__(self): Chris Angelico <rosuav@gmail.com> - 2016-04-27 03:30 +1000
        Re: def __init__(self): Marko Rauhamaa <marko@pacujo.net> - 2016-04-26 19:38 +0300
  Re: def __init__(self): Random832 <random832@fastmail.com> - 2016-04-26 09:49 -0400
  Re: def __init__(self): Gary Herron <gherron@digipen.edu> - 2016-04-26 07:25 -0700

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