From: Mark Woodward <markonlinux@...>
Date: 2007-11-26T19:45:06+09:00
Subject: Re: Moving files matching Regex

On Sun, 25 Nov 2007 20:59:46 +1100
Mark Woodward <markonlinux@internode.on.net> wrote:

thanks to all replies. Very informative.
I've benchmarked this and 'get_file_names2' is considerably quicker!
(if I'm benchmarking correctly?)

Could someone explain why? ie what is it about get_file_names2 that
makes it so much quicker? What is it about get_file_names that slows it
down?


def get_file_names
  fn=[]
  Find.find('./') do |path|
    Find.prune if File.basename(path) == 'sent'
    curr_file = File.basename(path)
    if curr_file =~ FILE_REGEX
      fn << curr_file
    end
  end
  fn
end


def get_file_names2
  fglob= %r{^(CAL|NCPH|GOH)\d{6}\.xls$}x
  all_files = Dir.glob("*")
  my_files  = all_files.grep(fglob)
end



Benchmark.bm(5) do |timer|
  timer.report('get_file_names') {10000.times {get_file_names}}
  timer.report('get_file_names2') {10000.times {get_file_names2}}
end


Results:

                 user       system     total     real
get_file_names   3.040000   0.700000   3.740000  (5.440394)
get_file_names2  0.570000   0.160000   0.730000  (0.997355)


cheers,

-- 
Mark