8011437.rb

#!/usr/bin/env ruby

require 'benchmark'

LETTERS = ('a'..'z').to_a.freeze

def random_customer_name
  name = [ ]
  
  (rand(10) + 1).times do
    name << LETTERS[rand(LETTERS.length)] * (rand(10) + 3)
  end

  name.join('.')
end

def customer_list
  list = ''
  
  10000.times do
    list << random_customer_name + "\n"
  end
  
  list
end

sample_customer_lists = [ ]

100.times do
  sample_customer_lists << customer_list.split(/\n/)
end

cycles = 10

Benchmark.bm do |bm|
  #      user     system      total        real
  #  0.740000   0.020000   0.760000 (  0.991042)
  bm.report {
    cycles.times do
      list = sample_customer_lists.pop
    
      list.each { |c| c.gsub!(/\./, ' ') }
    end
  }

  #      user     system      total        real
  #  0.680000   0.010000   0.690000 (  1.011136)
  bm.report {
    cycles.times do
      list = sample_customer_lists.pop
    
      list.collect! { |c| c.gsub(/\./, ' ') }
    end
  }

  #      user     system      total        real
  #  0.490000   0.020000   0.510000 (  0.628354)
  bm.report {
    cycles.times do
      list = sample_customer_lists.pop
    
      list.collect!{ |c| c.split('.').join(' ') }
    end
  }

  #      user     system      total        real
  #  0.090000   0.000000   0.090000 (  0.103968)
  bm.report {
    cycles.times do
      list = sample_customer_lists.pop
    
      list.collect!{ |c| c.tr!('.', ' ') }
    end
  }
end