1  
   2  class Array
   3    def to_ranges
   4      array = self.compact.uniq.sort
   5      ranges = []
   6      if !array.empty?
   7        # Initialize the left and right endpoints of the range
   8        left, right = self.first, nil
   9        array.each do |obj|
  10          # If the right endpoint is set and obj is not equal to right's successor 
  11          # then we need to create a range.
  12          if right && obj != right.succ
  13            ranges << Range.new(left,right)
  14            left = obj
  15          end
  16          right = obj
  17        end
  18        ranges << Range.new(left,right)
  19      end
  20      ranges
  21    end
  22  end