fastest_arrays_to_hash.rb

require 'benchmark'

def zip_it(array1,array2)
  Hash[array1.zip(array2)]
end


def naive(array1,array2)
  hash = {}

  index = 0
  length = array1.length
  while index < length
    hash[array1[index]] = array2[index]
    index+=1
  end

  hash
end


def smart_zip(array1,array2)
  hash = Hash.new
  array1.zip(array2) do |x,y|
    hash[x] = y
  end
  hash
end

def each_with_index(array1,array2)
  hash = Hash.new
  array1.each_with_index do |elem, idx|
    hash[elem] = array2[idx]
  end

  hash
end

def lazy(array1,array2)
  hash = Hash.new

  array1.each_with_object(array2.lazy) do |elem, elem2|
    hash[elem] = elem2.next
  end

  hash
end


[2,20,40,60,100].each do |i|

  array1 = (0..i).to_a
  array2 = (0..i).to_a

  puts
  puts "Benching #{i} elements"
  puts


  Benchmark.bmbm do |x|
    x.report("zip #{i}") do
      10000.times{zip_it(array1,array2)}
    end

    x.report("naive #{i}") do
      10000.times{naive(array1,array2)}
    end
    x.report("smart zip #{i}") do
      10000.times{smart_zip(array1,array2)}
    end

    x.report("each_with_index #{i}") do
      10000.times{each_with_index(array1,array2)}
    end

    x.report("lazy #{i}") do
      10000.times{lazy(array1,array2)}
    end
  end

end