index_by()
  public
  
    
    
Convert an enumerable to a hash. Examples:
  people.index_by(&:login)
    => { "nextangle" => <Person ...>, "chade-" => <Person ...>, ...}
  people.index_by { |person| "#{person.first_name} #{person.last_name}" }
    => { "Chade- Fowlersburg-e" => <Person ...>, "David Heinemeier Hansson" => <Person ...>, ...}
   
  
    Show source    
    
      
  def index_by
    inject({}) do |accum, elem|
      accum[yield(elem)] = elem
      accum
    end
  end