Updated Avdi's symbolize_keys

symbolize_keys.rb

def symbolize_keys(x)
  if x.is_a? Hash
    x.inject({}) do |result, (key, value)|
      new_key = case key
                when String then key.to_sym
                else key
                end
      new_value = case value
                  when Hash then symbolize_keys(value)
                  when Array then symbolize_keys(value)
                  else value
                  end
      result[new_key] = new_value
      result
    end
  elsif x.is_a? Array
    x.map {|el| symbolize_keys(el)}
  else
    x
  end
end