如何將哈希值投射到紅寶石中的對象？

Question

我正在使用Mongo，並將哈希存儲在數據庫中。 但是，稍后在檢索哈希時，不能再使用對象方法了嗎？ 如何將從數據庫中檢索到的哈希值轉換為TraitScore？

class TraitScore < Hash
  def initialize(attrs = {}, options = nil)
    self['net']    = attrs[:net]   || 0.0
    self['total']  = attrs[:total] || 0.0
    self['score']  = attrs[:score] || 0.0
  end

  def inc_net(val)
    self['net'] += val
  end

  def inc_total(val)
    self['total'] += (val || 0).abs
  end

  def set_score(score)
    self['score'] = score
  end
end

Answer 1

從源代碼來看，這正是TraitScore的initialize方法所做的。

irb(main):001:0> hash = {net: 0.0, total: 5, score: 7}
=> {:net=>0.0, :total=>5, :score=>7}
irb(main):002:0> hash.class
=> Hash
irb(main):003:0> object = TraitScore.new(hash)
=> {"net"=>0.0, "total"=>5, "score"=>7}
irb(main):004:0> object.class
=> TraitScore