test_array_hash_set.rb

#!/usr/bin/ruby -w
require 'benchmark'
require 'set'

array = (1..1_000_000).to_a
hash = {}
array.map {|x| hash[x] = nil}
a_set = array.to_set

Benchmark.bm(15) do |x|
    x.report("Array.include?") { 1000.times { array.include?(500_000) } }
    x.report("Hash.include?") { 1000.times { hash.include?(500_000) } }
    x.report("Set.include?") { 1000.times { a_set.include?(500_000) } }
end

##   user     system      total        real
##   Array.include?  38.730000   0.010000  38.740000 ( 38.853568)
##   Hash.include?    0.000000   0.000000   0.000000 (  0.000922)
##   Set.include?     0.000000   0.000000   0.000000 (  0.001652)