Bug #7245: Float.round result not as expected

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 1.9.3p286 (2012-10-12 revision 37164) [x86_64-darwin12.2.0]

[alexr (Alexander Rusa)]

In my second example below I would expect "1.01" as result.

1.9.3-p286 :001 > 1.05.round(1)
=> 1.1
1.9.3-p286 :002 > 1.005.round(2)
=> 1.0
1.9.3-p286 :003 > 1.006.round(2)
=> 1.01

Is this a bug or am I wrong?

[mame (Yusuke Endoh)]

• Status changed from Open to Rejected

This is the spec.

Float is internally stored in binary representation which cannot represent 1.005 precisely.
So the literal "1.005" becomes an approximate Float object actually less than its mathematical value.

$ ruby -e 'p (1.005 * 3)'
3.0149999999999997

--
Yusuke Endoh [e-mail]