$ ruby -v
ruby 2.2.0p0 (2014-12-25 revision 49005) [x86_64-darwin14]
$ irb
irb(main):001:0> 0.692 * 3
=> 2.0759999999999996
I just ran into these numbers by chance. Is this related to Why Are Floating Point Numbers Inaccurate?.
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Pat Wangrungarun
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1Yes, it is related to that. – Reinstate Monica -- notmaynard May 08 '15 at 19:26
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2Yep, and same in any other language (e.g. Python, Java,...) that uses the same floating point standard. – DNA May 08 '15 at 19:28
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Because of [IEEE-754 floating point numbers](http://en.wikipedia.org/wiki/IEEE_floating_point). – maerics May 08 '15 at 19:42
2 Answers
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Because floats are inaccurate, for arbitrary precision arithmetic in Ruby you can use BigDecimal:
require 'bigdecimal'
require 'bigdecimal/util'
("0.692".to_d * 3).to_s('F')
=> "2.076"
Casper
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Because BigDecimal from the standard library will work for this, but we can solve this problem by using round function -
(0.692 * 3).round(2) = 2.08
Amit Suroliya
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