From: The Higgs bozo <higgs.bozo@...>
Date: 2008-10-28T02:10:25+09:00
Subject: Re: float equality

guille lists wrote:
> I'm a bit lost here, shouldn't (0.1) and (1 - 0.9) be equals regarding
> the == operator?

Nope.  Floating-point is always inexact.  This is a computer thing, not 
a Ruby thing.  The issue applies to all languages everywhere which use 
floating point.

Here you can see the two values are slightly different:

irb(main):001:0> 1 - 0.9 == 0.1
=> false
irb(main):002:0> [1 - 0.9].pack("D")
=> "\230\231\231\231\231\231\271?"
irb(main):003:0> [0.1].pack("D")
=> "\232\231\231\231\231\231\271?"
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