Simple function to remove duplicates

remove_dups.rb

class Array
  def remove_dups!
    dup_count = Hash.new(0)
  	self.each do |val| 
  		dup_count[val] += 1
  	end
  	
  	dup_count.each do |val, count|
  		if count > 1
  			(count-1).times { self.delete_at self.rindex(val) }
  		end
  	end
  end
end

emails = ['jane@example.com', 'jon@example.com', 'jane@example.com', 'ron@example.com', 'ron@example.com', 'jon@example.com']
emails.remove_dups!
puts emails.to_s # ["jane@example.com", "jon@example.com", "ron@example.com"]