From: Kenta Murata <muraken@...>
Date: 2011-09-14T00:01:27+09:00
Subject: [ruby-core:39522] [Ruby 1.9 - Bug #4576] Range#step miss the last value, if end-exclusive and has float number


Issue #4576 has been updated by Kenta Murata.


Hi,

you can use BigDecimal as following:

ruby-1.9-head -rbigdecimal -ve 'p (BigDecimal("1.0")..BigDecimal("6.8")).step(BigDecimal("1.9")).to_a'
ruby 1.9.4dev (2011-09-06 trunk 33199) [x86_64-darwin11.1.0]
-e:1: warning: (...) interpreted as grouped expression
[#<BigDecimal:7fb9db05fd60,'0.1E1',9(18)>, #<BigDecimal:7fb9db05eed8,'0.29E1',18(36)>, #<BigDecimal:7fb9db05ec08,'0.48E1',18(36)>, #<BigDecimal:7fb9db05e960,'0.67E1',18(36)>]

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Bug #4576: Range#step miss the last value, if end-exclusive and has float number
http://redmine.ruby-lang.org/issues/4576

Author: Joey Zhou
Status: Closed
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: -


=begin
Hi, I find that:

* if: range.exclude_end? == true
* and: any one in [begin_obj, end_obj, step] is a true Float(f.to_i != f)
* and: unless begin_obj + step*int == end_obj
* then: the result will miss the last value.

for example:

 p (1...6.3).step.to_a # => [1.0, 2.0, 3.0, 4.0, 5.0], no 6.0
 p (1.1...6).step.to_a # => [1.1, 2.1, 3.1, 4.1], no 5.1
 p (1...6).step(1.1).to_a # => [1.0, 2.1, 3.2, 4.300000000000001], no 5.4

 p (1.0...6.6).step(1.9).to_a # => [1.0, 2.9], no 4.8
 p (1.0...6.7).step(1.9).to_a # => [1.0, 2.9, 4.8]
 p (1.0...6.8).step(1.9).to_a # => [1.0, 2.9, 4.8], no 6.7

Maybe the #step is ok on integers, but there's something wrong if the range is end-exclusive and contain float numbers.
=end



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