class Array

Frequency takes the existing array and returns an array of frequencies of

the items within the array

1, 1, 3, 3, 4, 4, 4, 5].frequency_list => [[1, 2], [3,2], [4,3], [5,1]

or if you want to do it by object property

class Person

attr_accessor
def initalizse(name)
  @name=name
end

end

freqs = [Person.new(“Jay”) Person.new(“Jay”), Person.new(“Joe”), Person.new(“Mike”)].frequency_list{|x| x.name} => [[<Person:Jay>, 2], [<Person:Jay>, 1], [<Person:Jay>, 1] ]

# File lib/bad_ass_extensions/array.rb, line 64
def frequency_list(&block)
  if block
    return self.group_by{|elem| block.call(elem)}.inject([]){|arr, group| arr << [group[0], group[1].length];arr}
  else
    return self.group_by{|elem| elem}.inject([]){|arr, group| arr << [group[0], group[1].length];arr}
  end
end

# Example

class Person

attr_accessor :type, :name, :source
def initialize(options)
  @type=options[:type]
  @name=options[:name]
  @source=options[:source]
end

end

type_sort_list = %w(User Admin Salesman) source_sort_list = %w(web email direct mail television) myarr = [] myarr << Person.new(:source=>“direct”, :type=>“Admin”, :name=>“Jason”) myarr << Person.new(:source=>“mail”, :type=>“User”, :name=>“Xavier”) myarr << Person.new(:source=>“email”, :type=>“User”, :name=>“Josh”) myarr << Person.new(:source=>“email”, :type=>“Salesman”, :name=>“Pablo”) myarr << Person.new(:source=>“web”, :type=>“User”, :name=>“Pat”) myarr << Person.new(:source=>“television”, :type=>“Salesman”, :name=>“Ross”)

# Sort by type sorted_by_type_myarr = myarr.sort_by_list(type_sort_list) do |item|

item.type

end puts sorted_by_type_myarr.to_yaml

# Sort by source sorted_by_source_myarr = myarr.sort_by_list(source_sort_list) do |item|

item.source

end puts sorted_by_source_myarr.to_yaml

# File lib/bad_ass_extensions/array.rb, line 37
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{|item| item[1]}.map{|item| item[0]}
end