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Re: 'complex' function with string argument.

References (3 earlier) <lg9rdm$us9$1@speranza.aioe.org> <11b58171-a99b-4ddf-8e6c-7b4f3169c60c@googlegroups.com> <87lhw6po53.fsf@elektro.pacujo.net> <d1f09443-f5d4-4ed6-880f-bc15810a1fdd@googlegroups.com> <87bnx233gd.fsf@elektro.pacujo.net>
From Ian Kelly <ian.g.kelly@gmail.com>
Date 2014-03-19 04:33 -0600
Subject Re: 'complex' function with string argument.
Newsgroups comp.lang.python
Message-ID <mailman.8276.1395225264.18130.python-list@python.org> (permalink)

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On Wed, Mar 19, 2014 at 4:09 AM, Marko Rauhamaa <marko@pacujo.net> wrote:
> wxjmfauth@gmail.com:
>
>> Le mercredi 19 mars 2014 09:51:20 UTC+1, Marko Rauhamaa a écrit :
>>> wxjmfauth@gmail.com:
>>> >>>> complex(2, 1+1j)
>>> > (1+1j)
>>>
>>> I find it neat, actually.
>>
>>>>> # tricky: yes, neat: no
>>>>> complex(1+1j, 2)
>> (1+3j)
>
> So complex(a, b) is documented to produce a+bj when a and b are integers
> or floats. What's more natural than saying it produces a+bj when a and b
> are complex numbers? It's a straightforward generalization that in no
> way violates the more limited documentation.

When is it ever useful though?  I only see a use for passing a as
complex if b is omitted, and I don't see any use for passing b as
complex.  If there's no use case, then it's just a confusing edge case
that will catch unsuspecting programmers who thought the data they
were passing in was real-valued when actually it wasn't.  It would be
better to raise an exception in either of the cases above, in my
opinion.  If you really want to form a complex a+bj from two other
complex numbers, there is always the explicit (a + b * 1j).

That said, complex numbers have been around since 1.4 or so, and
there's probably not much chance to change it now.

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Thread

'complex' function with string argument. Jayanth Koushik <jnkoushik@gmail.com> - 2014-03-15 09:26 -0700
  Re: 'complex' function with string argument. Mark H Harris <harrismh777@gmail.com> - 2014-03-17 11:18 -0500
    Re: 'complex' function with string argument. Chris Angelico <rosuav@gmail.com> - 2014-03-18 04:03 +1100
      Re: 'complex' function with string argument. Marko Rauhamaa <marko@pacujo.net> - 2014-03-17 20:15 +0200
        Re: 'complex' function with string argument. Ian Kelly <ian.g.kelly@gmail.com> - 2014-03-17 12:28 -0600
        Re: 'complex' function with string argument. Chris Angelico <rosuav@gmail.com> - 2014-03-18 05:59 +1100
          Re: 'complex' function with string argument. Marko Rauhamaa <marko@pacujo.net> - 2014-03-17 21:22 +0200
            Re: 'complex' function with string argument. Chris Angelico <rosuav@gmail.com> - 2014-03-18 06:32 +1100
            Re: 'complex' function with string argument. Steven D'Aprano <steve@pearwood.info> - 2014-03-18 04:08 +0000
      Re: 'complex' function with string argument. Mark H Harris <harrismh777@gmail.com> - 2014-03-17 13:20 -0500
    Re: 'complex' function with string argument. Steven D'Aprano <steve@pearwood.info> - 2014-03-18 04:52 +0000
      Re: 'complex' function with string argument. Chris Angelico <rosuav@gmail.com> - 2014-03-18 15:59 +1100
      Re: 'complex' function with string argument. Mark H Harris <harrismh777@gmail.com> - 2014-03-18 11:14 -0500
        Re: 'complex' function with string argument. wxjmfauth@gmail.com - 2014-03-19 00:30 -0700
          Re: 'complex' function with string argument. Marko Rauhamaa <marko@pacujo.net> - 2014-03-19 10:51 +0200
            Re: 'complex' function with string argument. wxjmfauth@gmail.com - 2014-03-19 02:52 -0700
              Re: 'complex' function with string argument. Marko Rauhamaa <marko@pacujo.net> - 2014-03-19 12:09 +0200
                Re: 'complex' function with string argument. Ian Kelly <ian.g.kelly@gmail.com> - 2014-03-19 04:33 -0600
                Re: 'complex' function with string argument. Marko Rauhamaa <marko@pacujo.net> - 2014-03-19 12:53 +0200
                Re: 'complex' function with string argument. Ian Kelly <ian.g.kelly@gmail.com> - 2014-03-19 13:35 -0600
                Re: 'complex' function with string argument. Skip Montanaro <skip@pobox.com> - 2014-03-19 06:04 -0500
                Re: 'complex' function with string argument. wxjmfauth@gmail.com - 2014-03-19 07:35 -0700
                Re: 'complex' function with string argument. Ian Kelly <ian.g.kelly@gmail.com> - 2014-03-19 12:45 -0600
  Re: 'complex' function with string argument. Mark Dickinson <mdickinson@enthought.com> - 2014-03-17 17:55 +0000
  Re: 'complex' function with string argument. Terry Reedy <tjreedy@udel.edu> - 2014-03-17 18:06 -0400
  Re: 'complex' function with string argument. Skip Montanaro <skip@pobox.com> - 2014-03-17 18:59 -0500
  Re: 'complex' function with string argument. Chris Angelico <rosuav@gmail.com> - 2014-03-18 11:16 +1100
  Re: 'complex' function with string argument. Skip Montanaro <skip@pobox.com> - 2014-03-17 20:07 -0500
  Re: 'complex' function with string argument. Christian Gollwitzer <auriocus@gmx.de> - 2014-03-18 08:04 +0100
    Re: 'complex' function with string argument. Chris Angelico <rosuav@gmail.com> - 2014-03-18 18:11 +1100
    Re: 'complex' function with string argument. Steven D'Aprano <steve@pearwood.info> - 2014-03-18 08:00 +0000
      Re: 'complex' function with string argument. Christian Gollwitzer <auriocus@gmx.de> - 2014-03-18 09:21 +0100
        Re: 'complex' function with string argument. Marko Rauhamaa <marko@pacujo.net> - 2014-03-18 16:00 +0200

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