Delete all empty/false elements from hash recursively

gistfile1.rb

# (v.respond_to?(:empty?) ? v.empty? : !v) is basically rails' .blank? in plain ruby
class Hash
  def delete_blank
    delete_if do |k, v|
      (v.respond_to?(:empty?) ? v.empty? : !v) or v.instance_of?(Hash) && v.delete_blank.empty?
    end
  end
end