let_the_benchmarks_begin.rb

for_vs_each.rb

# For vs. each
# Results:
#
#      user     system      total        real
#  0.340000   0.000000   0.340000 (  0.341422)
#  0.310000   0.000000   0.310000 (  0.326168)
require 'benchmark'

n = 500000

Benchmark.bm do |x|
  x.report do
    foo = nil
    bar = [1,2,3,4,5]
    n.times do
      for i in bar do
        foo = i
      end      
    end
  end
  x.report do
    foo = nil
    bar = [1,2,3,4,5]
    n.times do
      bar.each do |i|
        foo = i
      end
    end
  end  
end

good_to_know.rb

# Obvious if you think about it
# but hey it needed to be benched
# Results:
#
#      user     system      total        real
#  0.110000   0.000000   0.110000 (  0.105050)
#  0.470000   0.020000   0.490000 (  0.493622)
require 'benchmark'

n = 500000

Benchmark.bm do |x|
  x.report do
    something = {}
    n.times do
      something[:else] = 2
    end
  end
  x.report do
    n.times do 
      something ||= {}
      something[:else] = 2
    end
  end  
end