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Bug #5699

closed

Windowsで一部のFloat値が正しく扱えない

Added by oku (剛 奥山) over 10 years ago. Updated over 10 years ago.

Status:
Rejected
Priority:
Normal
Assignee:
-
Target version:
ruby -v:
ruby 1.9.2p290 (2011-07-09) [i386-mingw32]
Backport:
[ruby-dev:44918]

Description

Windows XP SP3にて、

ruby 1.9.2p290 (2011-07-09) [i386-mingw32] で、
x = 0.002877 #=> 0.0028770000000000002
となってしまいます。

ruby 1.8.7 (2011-06-30 patchlevel 352) [i386-mingw32] では、
x = 0.002877 #=> 0.002877
となります。

Updated by oku (剛 奥山) over 10 years ago

FAQでした、すみません。

1.9.2 は、より正しく表示出来るようになったということで
納得しました。

https://github.com/rdp/ruby_tutorials_core/wiki/ruby-talk-faq#floats_imprecise

1.1
=> 1.1 # in reality this probably doesn't equal exactly 1.1 deep down--but it's equal to 1.1's default so ruby 1.9.2 will display it as 1.1
0.9
=> 0.9
1.1-0.9
=> 0.20000000000000007 # now ruby 1.9.2 notices that "this 0.2 is not the same as the default float for 0.2" so it displays its full version to remind us of this fact.

Updated by ujihisa (Tatsuhiro Ujihisa) over 10 years ago

  • Status changed from Open to Rejected
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