set vs array

benchmark.rb

require 'benchmark'
require 'set'

some_numbers = []

1_000_000.times do
  num = rand(100_000)
  rand(5).times do 
    some_numbers << {:id => num}
  end
end


Benchmark.bmbm do |x|
  x.report("set") do
    some_numbers.inject(Set.new) do |set, numbers|
      set << numbers[:id]
    end
  end
  x.report("array") do
    some_numbers.inject([]) do |array, numbers|
      foo = numbers[:id]
      array << numbers[:id] if array.last != numbers[:id]
      array
    end
  end
end
__END__
Rehearsal -----------------------------------------
set     2.660000   0.010000   2.670000 (  2.675109)
array   2.740000   0.010000   2.750000 (  2.751495)
-------------------------------- total: 5.420000sec

            user     system      total        real
set     2.620000   0.000000   2.620000 (  2.627769)
array   2.550000   0.010000   2.560000 (  2.567725)