From: Grehom <grehom@...>
Date: 2006-01-05T00:32:58+09:00
Subject: Re: Newbie question about nested sort

Thanks everyone, very interesting.  The sort_by method certainly will
earn it's keep in my application as my test results show below

require 'benchmark'
include Benchmark

alphabet = ("abcdefghij")
char_freq = (1..100000).map {[alphabet[rand(9)].chr, rand(8)+1]}
bm(10) do |b|
   b.report("Sort by") { char_freq.sort_by {|a| [-a[1], a[0]] } }
   b.report("Sort")    { char_freq.sort {|a, b| (b[1]<=>a[1]).nonzero?
|| a[0]<=>b[0] } }
end

alphabet = ("abcdef")
char_freq = (1..100000).map {[alphabet[rand(5)].chr, rand(4)+1]}
bm(10) do |b|
   b.report("Sort by") { char_freq.sort_by {|a| [-a[1], a[0]] } }
   b.report("Sort")    { char_freq.sort {|a, b| (b[1]<=>a[1]).nonzero?
|| a[0]<=>b[0] } }
end

produces >>
C:\rubysrcs\Yahtzee>ruby -w test3.rb
                user     system      total        real
Sort by     1.469000   0.000000   1.469000 (  1.469000)
Sort        2.703000   0.000000   2.703000 (  2.703000)
                user     system      total        real
Sort by     0.766000   0.000000   0.766000 (  0.766000)
Sort        2.125000   0.016000   2.141000 (  2.141000)