bench/bench_loops.rb

   1 # Copied with permission from Antoni Cangiano's blog:
   2 # http://antoniocangiano.com/2008/03/25/inject-each-and-times-methods-much-slower-in-ruby-19
   3 require 'benchmark'
   4 include Benchmark
   5
   6 class Integer
   7   def sum_with_inject
   8     (1..self).inject(0) { |sum, i| sum + i }
   9   end
  10
  11   def sum_with_each
  12     sum = 0
  13     (1..self).each { |i| sum += i }
  14     sum
  15   end
  16
  17   def sum_with_times
  18     sum = 0
  19     (self+1).times { |i| sum += i}
  20     sum
  21   end
  22
  23   def sum_with_while
  24     sum, i = 0, 1
  25     while i <= self
  26       sum += i
  27       i += 1
  28     end
  29     sum
  30   end
  31 end
  32
  33 (1..8).each do |p|
  34   n = 10**p
  35   puts "=== 10^#{p} ==="
  36   benchmark do |x|
  37     x.report("inject: ") { n.sum_with_inject }
  38     x.report("each:   ") { n.sum_with_each }
  39     x.report("times:  ") { n.sum_with_times }
  40     x.report("while:  ") { n.sum_with_while }
  41   end
  42 end
  43