Sum and Average Virtual Attributes in ActiveRecord

gistfile1.rb

class ActiveRecord::Base

  # Totals the virtual attributes of a collection
  def self.vsum collection, v_attr
    total = 0
    collection.each { |collect| total += collect.method(v_attr.to_s).call } 
    return total
  end

  # Avarages the virtual attributes of a collection
  def self.vavg collection, v_attr 
    total = 0
    count = 0
    collection.each { |collect| total += collect.method(v_attr.to_s).call; count += 1 } 
    return total / count
  end
end