ruby - 在 Ruby 中返回嵌套哈希的最大深度的任何好方法

Question

Hash 对象如下所示，它同时具有数组和散列值，但嵌套总是发生在“children”数组的值处:

a = {"id" => "1", "children" => [{"id"=>"11", "children"=>[{"id"=>"111"}]}, {"id"=>"12", "children"=>[{"id"=>"121", "children"=>[{"id"=>"1211"}]}, {"id"=>"122"}]}]}
a.max_depth = 3

Answer 1

以下(非递归)实例方法 Hash#depth 返回所需的深度度量。我添加了一个 puts 语句来显示中间计算。

class Hash
  def depth
    arr = values
    d = 0
    loop do
      arr = arr.flatten.select { |e| e.is_a? Hash }
      break d if arr.empty?
      d += 1
      arr = arr.map(&:values)
      puts "d = #{d}, arr = #{arr}"
    end
  end
end

a.depth
d = 1, arr = [["11", [{"id"=>"111"}]], ["12", [{"id"=>"121", "children"=>
                [{"id"=>"1211"}]}, {"id"=>"122"}]]]
d = 2, arr = [["111"], ["121", [{"id"=>"1211"}]], ["122"]]
d = 3, arr = [["1211"]]
  #=> 3