From: "Peña, Botp" <botp@...>
Date: 2008-07-04T16:19:05+09:00
Subject: Re: thoughts on a more generic Array#partition function

From: Yukihiro Matsumoto [mailto:matz@ruby-lang.org] 
# <botp@delmonte-phil.com> writes:
# |current test:
# |
# |1.9   not sorted
# |1.8.6 not sorted
# |1.8.7 sorted
# |
# |i prefer 1.8.7 default behaviour
# Hmm, from my understanding, 1.9 preserves the order, prior version
# does not.  Could you show us the test you got the above conclusion?

sir Matz, as requested,

> [RUBY_VERSION, RUBY_RELEASE_DATE, RUBY_REVISION]
=> ["1.9.0", "2008-06-20", 17482]

> RUBY_PLATFORM
=> "i386-mswin32"

> a = [ 1, 2, 3, 4, 7, 9, 11, 12, 13, 14 ]
=> [1, 2, 3, 4, 7, 9, 11, 12, 13, 14]

> a.group_by { |i| i % 3 }
=> {1=>[1, 4, 7, 13], 2=>[2, 11, 14], 0=>[3, 9, 12]}

    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    at this point, 1.9 and 1.8.7 differs

> h=a.group_by { |i| i % 3 }
=> {1=>[1, 4, 7, 13], 2=>[2, 11, 14], 0=>[3, 9, 12]}  

> h.values
=> [[1, 4, 7, 13], [2, 11, 14], [3, 9, 12]]

kind regards -botp