Re: Hash Surprises with Fixnum, #hash, and #eql?

From	Robert Klemme <shortcutter@googlemail.com>
Newsgroups	comp.lang.ruby
Subject	Re: Hash Surprises with Fixnum, #hash, and #eql?
Date	2011-04-07 08:43 -0500
Organization	Service de news de lacave.net
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On Thu, Apr 7, 2011 at 3:21 PM, Phillip Gawlowski
<cmdjackryan@googlemail.com> wrote:
> On Thu, Apr 7, 2011 at 1:53 PM, Robert Klemme
> <shortcutter@googlemail.com> wrote:
>>
>> Actually it's Numeric which is correct because not every Complex _is a_ Float!
>
> Unless you convert from polar form* to Cartesian form:
>
> Let's take "45e^(j * 44°)":
>
> 32.37029101523930127102246035055203587038080515238845970760... +
> 31.25962667065487789953828347402088034639160866937838052053... i
>
> From <http://www.wolframalpha.com/input/?i=45*e^%2844%C2%B0i%29>.
>
> * Which you are much more likely to encounter than the Cartesian form,
> considering complex numbers are most useful when dealing with wave
> forms.

My math is a bit rusty in that area, but I don't think your argument
holds: cartesian and polar are just two ways to represent a complex
number.  But this does not change numeric properties of the class of
complex numbers.  No matter what representation you use, (0+1i) is
neither a real number (what float conceptually models) nor a rational
number (what float technically implements).  Instead, real and
rational numbers are both subsets of complex.

If you see inheritance as "is a" relationship then inheritance would
be Rational < Real < Complex but not the other way round.  Otherwise
you cannot use a subclass instance everywhere you were using a
superclass instance.

Further links:

http://en.wikipedia.org/wiki/Rational_number
http://en.wikipedia.org/wiki/Real_number
http://en.wikipedia.org/wiki/Complex_number

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

Thread

Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-07 14:01 +1000
  Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-07 04:19 -0500
    Re: Hash Surprises with Fixnum, #hash, and #eql? Phillip Gawlowski <cmdjackryan@googlemail.com> - 2011-04-07 06:20 -0500
      Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-07 06:53 -0500
        Re: Hash Surprises with Fixnum, #hash, and #eql? Phillip Gawlowski <cmdjackryan@googlemail.com> - 2011-04-07 08:21 -0500
          Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-07 08:43 -0500
            Re: Hash Surprises with Fixnum, #hash, and #eql? Phillip Gawlowski <cmdjackryan@googlemail.com> - 2011-04-07 09:02 -0500
              Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-07 09:28 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Phillip Gawlowski <cmdjackryan@googlemail.com> - 2011-04-07 09:49 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-07 10:11 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Phillip Gawlowski <cmdjackryan@googlemail.com> - 2011-04-07 10:31 -0500
              Re: Hash Surprises with Fixnum, #hash, and #eql? Brian Candler <b.candler@pobox.com> - 2011-04-07 11:06 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Vincent Manis <vmanis@telus.net> - 2011-04-07 17:42 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-08 01:55 -0500
    Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-08 17:29 +1000
      Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-08 05:12 -0500
        Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-09 11:21 +1000
          Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-10 19:02 -0500
            Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-11 13:17 +1000
              Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-12 04:09 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-13 12:02 +1000
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-13 00:51 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-13 16:32 +1000
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-13 07:23 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-14 07:38 +1000
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-14 00:36 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-14 15:55 +1000
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-19 17:41 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-21 12:49 +1000
                Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-21 06:28 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-21 22:32 +1000
                Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-21 08:51 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? John W Higgins <wishdev@gmail.com> - 2011-04-21 11:11 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-27 00:33 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-27 01:44 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-27 16:22 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-04-27 00:23 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-30 17:43 +1000
                Re: Hash Surprises with Fixnum, #hash, and #eql? Charles Oliver Nutter <headius@headius.com> - 2011-05-01 23:01 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Robert Klemme <shortcutter@googlemail.com> - 2011-04-13 02:08 -0500
                Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-14 07:36 +1000
      Re: Hash Surprises with Fixnum, #hash, and #eql? Xavier Noria <fxn@hashref.com> - 2011-04-08 19:00 -0500
        Re: Hash Surprises with Fixnum, #hash, and #eql? Clifford Heath <no@spam.please.net> - 2011-04-09 11:22 +1000
  Re: Hash Surprises with Fixnum, #hash, and #eql? Mazi Ayışığı <mazi.ayisigi@gmail.com> - 2011-04-07 17:16 -0700

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