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Re: I am never going to complain about Python again

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On 11 October 2013 10:11, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> On Fri, 11 Oct 2013 09:17:37 +0100, Joshua Landau wrote:
>
>> On 11 October 2013 03:08, Steven D'Aprano
>> <steve+comp.lang.python@pearwood.info> wrote:
>>>
>>> Given:
>>>
>>> x ∈ ℝ, x = 2  (reals)
>>> y ∈ ℕ, y = 2  (natural numbers)
>>>
>>> we have x = y, but since 1/y is undefined (there is no Natural number
>>> 1/2), 1/x != 1/y.
>>
>> Surely 1/y is perfectly well defined, as only y, not 1/y, is constrained
>> to the natural numbers.
>
> Context is important, and usually implied. 1/y within the natural numbers
> is treated in the same way as sqrt(-1) within the reals.

I don't know; a rational tends to be described as any number of the
form x/y where x, y ∈ ℕ. Hence I don't agree that it's reasonable to
ever assume that 1/y has to exist in the same space as y unless
explicitly stated or generally working within, say, the integers.
Neither of those are remotely true of Python so I don't see how this
point is relevant when discussing Python's concept of equality.

> Try it on your
> calculator, and chances are very good you'll get an error. Try it in
> Python 2, or nearly any other programming language (but not Python 3),
> and again, chances are you'll get an error.

*Remains unconvinced.* None of that seems to actually matter.

> If you implicitly decide to promote entities, then of course you can
> promote y to a real then take the invoice.

I'm not. I'm just not applying the restrictions on y to the function it's in.

> But that trick still doesn't
> work for the original example, int(0.0) == int(0+0j) because promoting 0
> to complex doesn't help, you have to demote 0+0j to real and that's
> ambiguous.

I agree on this. The correct interpretation of

    0.0 == 0 + 0j

is, of course

    complex(0.0) == 0 + 0j

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I am never going to complain about Python again Steven D'Aprano <steve@pearwood.info> - 2013-10-10 04:36 +0000
  Re: I am never going to complain about Python again Chris Angelico <rosuav@gmail.com> - 2013-10-10 15:50 +1100
  Re: I am never going to complain about Python again Chris Rebert <clp2@rebertia.com> - 2013-10-09 22:26 -0700
  Re: I am never going to complain about Python again Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-10 06:39 +0100
  Re: I am never going to complain about Python again Christian Gollwitzer <auriocus@gmx.de> - 2013-10-10 08:41 +0200
  Re: I am never going to complain about Python again "Frank Millman" <frank@chagford.com> - 2013-10-10 10:23 +0200
  Re: I am never going to complain about Python again MRAB <python@mrabarnett.plus.com> - 2013-10-10 12:10 +0100
  Re: I am never going to complain about Python again Tim Chase <python.list@tim.thechases.com> - 2013-10-10 06:43 -0500
  Re: I am never going to complain about Python again "Frank Millman" <frank@chagford.com> - 2013-10-10 13:44 +0200
  Re: I am never going to complain about Python again Roy Smith <roy@panix.com> - 2013-10-10 09:09 -0400
    Re: I am never going to complain about Python again Neil Cerutti <neilc@norwich.edu> - 2013-10-10 15:51 +0000
      Re: I am never going to complain about Python again Rotwang <sg552@hotmail.co.uk> - 2013-10-10 16:57 +0100
        Re: I am never going to complain about Python again MRAB <python@mrabarnett.plus.com> - 2013-10-10 17:10 +0100
          Re: I am never going to complain about Python again Neil Cerutti <neilc@norwich.edu> - 2013-10-10 17:48 +0000
            Re: I am never going to complain about Python again Ian Kelly <ian.g.kelly@gmail.com> - 2013-10-10 12:35 -0600
              Re: I am never going to complain about Python again Neil Cerutti <neilc@norwich.edu> - 2013-10-10 18:49 +0000
            Re: I am never going to complain about Python again Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2013-10-10 20:47 +0100
              Re: I am never going to complain about Python again Neil Cerutti <neilc@norwich.edu> - 2013-10-10 19:54 +0000
            Re: I am never going to complain about Python again Cameron Simpson <cs@zip.com.au> - 2013-10-11 08:52 +1100
            Re: I am never going to complain about Python again Roy Smith <roy@panix.com> - 2013-10-10 20:07 -0400
              Is this the room for an argument? John Ladasky <john_ladasky@sbcglobal.net> - 2013-10-10 21:26 -0700
                Re: Is this the room for an argument? Roy Smith <roy@panix.com> - 2013-10-11 09:49 -0400
            Re: I am never going to complain about Python again Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-11 02:23 +0000
              Re: I am never going to complain about Python again Neil Cerutti <neilc@norwich.edu> - 2013-10-11 12:31 +0000
    Re: I am never going to complain about Python again Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-10-10 20:09 -0400
    Re: I am never going to complain about Python again Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-11 02:08 +0000
      Re: I am never going to complain about Python again Joshua Landau <joshua@landau.ws> - 2013-10-11 09:17 +0100
        Re: I am never going to complain about Python again Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-10-11 09:11 +0000
          Re: I am never going to complain about Python again Chris Angelico <rosuav@gmail.com> - 2013-10-11 20:52 +1100
          Re: I am never going to complain about Python again Joshua Landau <joshua@landau.ws> - 2013-10-11 17:56 +0100

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