From: Gyoung-Yoon Noh <nohmad@...>
Date: 2005-06-02T04:09:03+09:00
Subject: Re: Method Chaining Issues

On 6/2/05, Nikolai Weibull
<mailing-lists.ruby-talk@rawuncut.elitemail.org> wrote:
> It should also be pointed out that the non-destructive version of sub
> (i.e., String#sub) method often turns out to be faster than the
> destructive one (i.e., String#sub!),
>         nikolai
> 

No, what you said are inverted.
Some non-destructive methods are usually implemented by
simply copying reference after calling destructive method.
It looks like:

def sort(ary):
  sort!(ary)
  return ary
end

This is a benchmark results.

$ cat destructive.rb
require 'benchmark'

Benchmark.bmbm do |bm|
  bm.report("Destructive") do
    1000.times do
      ary = (0..10000).to_a
      ary.reverse!
      ary.sort!
    end
  end
  bm.report("Non-destructive") do
    1000.times do
      ary = (0..10000).to_a
      ary.reverse.sort
    end
  end
end

$ ruby destructive.rb
Rehearsal ---------------------------------------------------
Destructive       2.910000   0.000000   2.910000 (  2.904260)
Non-destructive   3.110000   0.000000   3.110000 (  3.116915)
------------------------------------------ total: 6.020000sec

                      user     system      total        real
Destructive       2.930000   0.000000   2.930000 (  2.935663)
Non-destructive   3.170000   0.010000   3.180000 (  3.171050)

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