ruby - 将带括号的字符串转换为树，Ruby

Question

我有一个字符串 "Animals ( Reptiles Birds ( Eagles Pigeons Crows ) )" 我需要返回:

a = [
  {
    "Animals" => [
      {
        "Reptiles" => nil
      },
      {
        "Birds" => [
          { "Eagles" => nil },
          { "Pigeons" => nil },
          { "Crows" => nil }
        ]
      }
    ]
  }
]

我不明白我该怎么做。 我在哪里可以找到一些例子或者我可以在谷歌中搜索什么？

Answer 1

这是将字符串转换为数组的一种方法。

代码

def arrayify(arr)
  a = split_arr(arr)
  a.map do |h|
    k = h.keys.first
    v = h.values.first
    case v
    when Array then { k => arrayify(v) }
    else { k=>v }
    end
  end
end

def split_arr(arr)
  a = []
  while arr.any?
    word = arr.shift
    if arr.empty? || arr.first != ?(
      a << { word=>nil }
    else
      arr.shift
      close_count = 0
      b = []
      loop do
        token = arr.shift
        case token
        when ?)
          break if close_count == 0
          close_count -= 1
        when ?( then close_count += 1
        end
        b << token
      end
      a << { word=>b }
    end
  end
  a
end

示例

str = "Animals ( Reptiles Birds ( Eagles Pigeons Crows ) ) Foods ( " +
      "Snacks Breakfast ( Pancakes Waffles ) )"

arrayify(str.split)

  #=> [{"Animals"=>[{"Reptiles" =>nil},
  #                 {"Birds"    =>[{"Eagles" =>nil},
  #                                {"Pigeons"=>nil},
  #                                {"Crows"  =>nil}
  #                               ]
  #                 }
  #                ]
  #    },
  #    {"Foods"  =>[{"Snacks"   =>nil},
  #                 {"Breakfast"=>[{"Pancakes"=>nil},
  #                                {"Waffles" =>nil}
  #                               ]
  #                 }
  #                ]
  #    }
  #   ]