ruby hash symbolize keys recursively.rb

def symbolize_keys(obj)
      case obj
      when Array
        obj.inject([]){|res, val|
          res << case val
          when Hash, Array
            symbolize_keys(val)
          else
            val
          end
          res
        }
      when Hash
        obj.inject({}){|res, (key, val)|
          nkey = case key
          when String
            key.to_sym
          else
            key
          end
          nval = case val
          when Hash, Array
            symbolize_keys(val)
          else
            val
          end
          res[nkey] = nval
          res
        }
      else
        obj
      end
    end

Hello. That is expected. That is how a string gets converted to a symbol. What you are looking for is key.underscore.to_sym. Feel free to update the code for your own needs. You need activesupport gem for that though

@softbrada Thank you for this. I use your code as core extension of the Hash class. This way I avoid to use larger Rails gems.

class Hash
  def symbolize_keys
    case self
    when Array
      self.inject([]){|res, val|
        res << case val
        when Hash, Array
          symbolize_keys(val)
        else
          val
        end
        res
      }
    when Hash
      self.inject({}){|res, (key, val)|
        nkey = case key
        when String
          key.to_sym
        else
          key
        end
        nval = case val
        when Hash, Array
          symbolize_keys(val)
        else
          val
        end
        res[nkey] = nval
        res
      }
    else
      self
    end
  end
end