Comparing for Array#each against for x in Array

iterator_benchmark.rb

require 'benchmark'

array = (1..1000000).map { rand }

Benchmark.bmbm do |x|
  x.report("for:") { for num in array; next; end }
  x.report("each:")  { array.each { |x| next }  }
end


# Output, 2 different runs on 1.9.3:

➜  code  ruby iterators.rb
Rehearsal -----------------------------------------
for:    0.150000   0.000000   0.150000 (  0.154021)
each:   0.140000   0.000000   0.140000 (  0.142896)
-------------------------------- total: 0.290000sec

            user     system      total        real
for:    0.160000   0.000000   0.160000 (  0.160215)
each:   0.140000   0.000000   0.140000 (  0.147743)

➜  code  ruby iterators.rb
Rehearsal -----------------------------------------
for:    0.160000   0.000000   0.160000 (  0.160084)
each:   0.150000   0.000000   0.150000 (  0.147410)
-------------------------------- total: 0.310000sec

            user     system      total        real
for:    0.160000   0.000000   0.160000 (  0.164363)
each:   0.150000   0.000000   0.150000 (  0.147960)

# and on 2.0.0
➜  code  ruby iterators.rb
Rehearsal -----------------------------------------
for:    0.050000   0.000000   0.050000 (  0.048878)
each:   0.040000   0.000000   0.040000 (  0.045567)
-------------------------------- total: 0.090000sec

            user     system      total        real
for:    0.040000   0.000000   0.040000 (  0.047812)
each:   0.050000   0.000000   0.050000 (  0.045822)

➜  code  ruby iterators.rb
Rehearsal -----------------------------------------
for:    0.050000   0.000000   0.050000 (  0.048716)
each:   0.050000   0.000000   0.050000 (  0.046151)
-------------------------------- total: 0.100000sec

            user     system      total        real
for:    0.050000   0.000000   0.050000 (  0.048347)
each:   0.040000   0.000000   0.040000 (  0.045965)