From: "nobu (Nobuyoshi Nakada)" <nobu@...>
Date: 2013-04-20T11:31:35+09:00
Subject: [ruby-core:54475] [Backport 200 - Backport #8299][Rejected] Minor error in float parsing


Issue #8299 has been updated by nobu (Nobuyoshi Nakada).

Status changed from Open to Rejected

Just -1.1505945e-5 is not accurately representable in binary format.
----------------------------------------
Backport #8299: Minor error in float parsing
https://bugs.ruby-lang.org/issues/8299#change-38779

Author: bobjalex (Bob Alexander)
Status: Rejected
Priority: Low
Assignee: 
Category: 
Target version: 


I encountered a float that either parses [slightly] differently (or converts to string differently) in Ruby than it does in Python or Java. This looks like a  Ruby bug since the result "looks" incorrect.

It is easily reproduced by entering the magic number (-1.1505945E-5) into irb. It behaves the same in 2.0 and 1.9. I'm using Windows.

Below is an irb session that demonstrates. Also included are JRuby and Python trials that show better behavior.

This issue is not causing me any problems, but just in case someone there is interested in looking into it...

Bob

>ruby -v
ruby 2.0.0p0 (2013-02-24) [i386-mingw32]

>irb
irb(main):001:0> RUBY_VERSION
=> "2.0.0"
irb(main):002:0> -1.1505945E-5
=> -1.1505945000000001e-05

>ruby19 -v
ruby 1.9.3p392 (2013-02-22) [i386-mingw32]

>irb19
irb(main):001:0> RUBY_VERSION
=> "1.9.3"
irb(main):002:0> -1.1505945E-5
=> -1.1505945000000001e-05
irb(main):002:0>

>jirb
irb(main):001:0> -1.1505945E-5
=> -1.1505945e-05

>python
Python 2.7.4rc1 (default, Mar 24 2013, 14:34:32) [MSC v.1500 32 bit (Intel)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>> -1.1505945E-5
-1.1505945e-05
>>> repr(-1.1505945E-5)
'-1.1505945e-05'




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