ruby 嵌套哈希

Question

我只是有一个简单的问题，请考虑这段代码:

class Hash
  def value_for(keys, value)
    common = self
    while keys.size > 1 and !common.nil?
      common = common[keys.shift] || { }
    end
    common[keys.last] = value
  end
end

通过这段代码，我希望能够通过传递嵌套节点数组和应该分配的值来创建嵌套哈希。

它应该像下面这样工作:

hash = {
  "message" => "hello world"
}

hash.value_for [ "nested", "message" ], "hello world"

hash
#=> {
       "message" => "hello world",
       "nested" => {
         "message" => "hello world"
       }
    }

hash.value_for [ "second", "nested", "message" ], "hello world"

hash
#=> {
       "message" => "hello world",
       "nested" => {
         "message" => "hello world"
       },
       "second" => {
         "nested" => {
           "message" => "hello world"
         }
       }
    }

出于某种原因，我的代码在创建新哈希时不起作用。我怀疑它与 common = common[keys.shift] || 有关{}

有人可以帮帮我吗？我觉得我错过了一些愚蠢的东西......

非常感谢

Answer 1

你可以这样做:

class Hash
  def value_for((*keys, last), value)
    _h = nil
    keys.inject(self){|h, k| _h = h[k] ||= {}}
    _h[last] = value
  end
end