hash.rb

require 'benchmark'

array = []
1000000.times do
  array << Random.rand
end

Benchmark.bm do |x|
  x.report("Insert") do 
    h = {}

    array.each do |a|
      h[a] = true
    end
  end
  x.report("Pass Array") do
    a2 = array.map { |n| [n, true] }
    h = Hash.new()
  end
end

            user     system      total        real
Insert      0.240000   0.020000   0.260000 (  0.235189)
Pass Array  0.140000   0.010000   0.150000 (  0.135472)