sort_array_by_external_sort_list.rb

require "rubygems"
require "activesupport"

class Person
  attr_accessor :name, :age
  def initialize(name, age)
    @name=name
    @age=age
  end
end

class Array
	def	sort_by_list(ordered_list, &block)
	  new_ol = ordered_list.inject({}){|new_hash, sort_item| new_hash[sort_item] = ordered_list.index(sort_item); new_hash}
    sorted = self.map{|item| [item, new_ol[block.call(item)] || 0]}.sort_by{|cred| cred[1]}.map{|cred| cred[0]}
  end
end

my_list = [
  Person.new("Jason", "30"),
  Person.new("Josh", "28"),
  Person.new("Ross", "27"),
  Person.new("Danny", "27"),
  Person.new("Pat", "23")
]




sort_list = ["Josh", "Jason", "Danny", "Pat", "Ross"]


sorted_list = my_list.sort_by_list(sort_list) do |item|
  item.name
end

puts my_list.to_yaml

puts sorted_list.to_yaml