Hashのkeyをflatにする

何階層にも入れ子になっているHashのKeyを'_'で結合してフラットにします。

#!/usr/bin/env ruby

require "awesome_print"

def flatten_key(hash, key = "", result = {})
  hash.each do |k, v|
    k2 = "#{key} #{k}"

    if v.is_a?(Hash)
      flatten_key(v, k2, result)
    else
      result[k2.strip.gsub(" ", "_").to_sym] = v
    end
  end

  result
end


ap flatten_key(
  {
    studio3104: { sex: "male", age: "young", favorite: { tsukemen: "warito", sushi: "any" } },
    kenjiskywalker: { sex: "male", age: "ojisan", },
  }
)

{
                  :studio3104_sex => "male",
                  :studio3104_age => "young",
    :studio3104_favorite_tsukemen => "warito",
       :studio3104_favorite_sushi => "any",
              :kenjiskywalker_sex => "male",
              :kenjiskywalker_age => "ojisan"
}