從ruby中的嵌套哈希數組中搜索鍵值

Question

我有嵌套哈希數組，

@a = [{"id"=>"5", "head_id"=>nil,
         "children"=>
             [{"id"=>"19", "head_id"=>"5",
                 "children"=>
                     [{"id"=>"21", "head_id"=>"19", "children"=>[]}]},
             {"id"=>"20", "head_id"=>"5",
                 "children"=>
                     [{"id"=>"22", "head_id"=>"20", "children"=>[]}, {"id"=>"23"}]
             }]
     }]

我需要所有具有鍵名稱'id'的值的數組。 比如@b = [5,19,21,20,22,23]我已經試過這個'@a.find {| h | H [ 'ID']}`。 有誰知道如何得到這個？

謝謝。

Answer 1

您可以為Array類對象創建新方法。

class Array
  def find_recursive_with arg, options = {}
    map do |e|
      first = e[arg]
      unless e[options[:nested]].blank?
        others = e[options[:nested]].find_recursive_with(arg, :nested => options[:nested])
      end
      [first] + (others || [])
    end.flatten.compact
  end
end

使用這種方法就像

@a.find_recursive_with "id", :nested => "children"

Answer 2

它可以這樣做，使用recursion

def traverse_hash
  values = []
  @a = [{"id"=>"5", "head_id"=>nil,
     "children"=>
         [{"id"=>"19", "head_id"=>"5",
             "children"=>
                 [{"id"=>"21", "head_id"=>"19", "children"=>[]}]},
         {"id"=>"20", "head_id"=>"5",
             "children"=>
                 [{"id"=>"22", "head_id"=>"20", "children"=>[]}, {"id"=>"23"}]
         }]
 }] 
 get_values(@a)
end

def get_values(array)   
  array.each do |hash|        
    hash.each do |key, value|
      (value.is_a?(Array) ? get_values(value) : (values << value)) if key.eql? 'id'
    end
  end    
end