From: MonkeeSage <MonkeeSage@...>
Date: 2007-11-27T17:40:02+09:00
Subject: Re: Moving files matching Regex

Since all the matches are xsl files, the function can be faster using
a glob for "*.xsl". Dir.entries is slower.

$ cat test.rb && ./test.rb
#!/usr/bin/env ruby

require 'find'
require 'fileutils'
require 'benchmark'

def get_file_names
  Dir.glob("*.xsl").select { | e |
    e =~ /^(CAL|NCPH|GOH)\d{6}\.xsl$/
  }
end

def get_file_names1
  Dir.glob("*.xsl").grep(/^(CAL|NCPH|GOH)\d{6}\.xsl$/)
end

def get_file_names2
  Dir.entries('.').select { | e |
    e =~ /^(CAL|NCPH|GOH)\d{6}\.xsl$/
  }
end

n = 10000
Benchmark.bm(5) { |x|
  x.report('get_file_names ') { n.times { get_file_names  } }
  x.report('get_file_names1') { n.times { get_file_names1 } }
  x.report('get_file_names1') { n.times { get_file_names2 } }
}

           user     system      total        real
get_file_names   0.210000   0.330000   0.540000 (  0.566366)
get_file_names1  0.270000   0.310000   0.580000 (  0.602565)
get_file_names1  0.680000   0.310000   0.990000 (  1.114583)

Regards,
Jordan