From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2007-09-25T17:31:29+09:00
Subject: Re: Extract numbers from string

On 9/25/07, Pe�a, Botp <botp@delmonte-phil.com> wrote:
> From: David A. Black [mailto:dblack@rubypal.com]
>
> #Don't forget \D:
> #
> #   old_num.gsub(/\D/, "")

I always wanted try the benchmark stuff, and this seemed like a good
opportunity :-).

cat remove_nondigits.rb && ruby remove_nondigits.rb
# remove_nondigits.rb
# 25 September 2007
#

require 'benchmark'

n = 100_000
old_num = "(555) 55-555-55"

Benchmark.bmbm do |x|
    x.report("scan") do
      n.times {old_num.scan(/\d/).join}
    end
    x.report("gsub") do
      n.times {old_num.gsub(/[^\d]/,"")}
    end
    x.report("gsub2") do
      n.times {old_num.gsub(/\D/, "")}
    end
    x.report("tr") do
      n.times {old_num.tr("^0-9","")}
    end
    x.report("delete") do
      n.times {old_num.delete("^0-9")}
    end
    x.report("split") do
      n.times {old_num.split(/[^\d]/).join}
    end
end
Rehearsal ------------------------------------------
scan     1.080000   0.000000   1.080000 (  1.144654)
gsub     0.380000   0.010000   0.390000 (  0.403057)
gsub2    0.390000   0.010000   0.400000 (  0.416074)
tr       0.290000   0.020000   0.310000 (  0.320764)
delete   0.270000   0.010000   0.280000 (  0.294078)
split    0.700000   0.000000   0.700000 (  0.714139)
--------------------------------- total: 3.160000sec

             user     system      total        real
scan     1.080000   0.020000   1.100000 (  1.101550)
gsub     0.380000   0.010000   0.390000 (  0.404968)
gsub2    0.380000   0.010000   0.390000 (  0.409364)
tr       0.290000   0.020000   0.310000 (  0.318723)
delete   0.280000   0.010000   0.290000 (  0.294650)
split    0.700000   0.000000   0.700000 (  0.713261)

So it seems that in terms of speed, delete wins, second place for tr,
and in the fight between [^\d] and \D the first one wins by a little
(very little) margin :-).

Cheers,

Jesus.