values_at vs. map

gistfile1.rb

require 'benchmark'

n = 1000
Benchmark.bm do |bm|
  keys = (1..10000).to_a
  hash = Hash[keys.zip(keys)]

  bm.report do
    n.times do
      keys.map{|key| hash[key] }
    end
  end

  bm.report do
    n.times do
      hash.values_at(*keys)
    end
  end
end


# ruby-2.0.0-p195
#        user     system      total        real
#   2.010000   0.060000   2.070000 (  2.074412)
#   1.130000   0.050000   1.180000 (  1.191744)

# jruby-1.7.4
#       user     system      total        real
#   1.680000   0.010000   1.690000 (  1.148000)
#   0.450000   0.020000   0.470000 (  0.410000)