arrays - 使用键数组遍历嵌套的 Ruby 哈希

Question

给定一个包含 n 层嵌套值的哈希值、一个字段名和一个路径

contact = {
  "Email" => "bob@bob.com",
  "Account" => {
    "Exchange" => true,
    "Gmail" => false,
    "Team" => {
      "Closing_Sales" => "Bob Troy",
      "Record" => 1234
    }
  }
}

field = "Record"
path = ["Account", "Team"] #Must support arbitrary path length

如何定义一种方法来检索路径末尾的字段值。

def get_value(hash, field, path)
  ?
end

get_value(contact, "Record", ["Account", "Team"])
=> 1234

Answer 1

让我们将“字段”视为“路径”的最后一个元素。那就简单了

def grab_it(h, path)
  h.dig(*path)
end

grab_it contact, ["Account", "Team", "Record"]
  #=> 1234 
grab_it contact, ["Account", "Team", "Rabbit"]
  #=> nil
grab_it(contact, ["Account", "Team"]
  # => {"Closing_Sales"=>"Bob Troy", "Record"=>1234} 
grab_it contact, ["Account"]
  #=> {"Exchange"=>true, "Gmail"=>false, "Team"=>{"Closing_Sales"=>"Bob Troy",
  #    "Record"=>1234}} 

Hash#dig在 v2.3 中添加。