如果值递归包含字符串，Ruby 返回顶级哈希键

Question

我有下面的数据结构，我试图返回顶级键（lo、eth0 或 eth1），如果它的值中任意递归和任意深度是给定的字符串。然后在找到字符串的第一个实例后终止搜索。

Find key/value pairs deep inside a hash containing an arbitrary number of nested hashes and arrays 这有点类似于我正在尝试做的事情，但我无法将其映射到我自己的问题

h.find{ |k,v| break k if v.include? "number" }
 => "eth0"

h.find{ |k,v| break k if v.include? "10.0.128.26" }
 => nil
#Should return eth0

我想知道如何通常使用这样的嵌套数据结构，但我会满足于能够在特定的子哈希中专门搜索，在我的例子中是地址。

    h = \
    {"lo"=>
      {"mtu"=>"65536",
       "flags"=>["LOOPBACK", "UP", "LOWER_UP"],
       "encapsulation"=>"Loopback",
       "addresses"=>
        {"127.0.0.1"=>
          {"family"=>"inet",
           "prefixlen"=>"8",
           "netmask"=>"255.0.0.0",
           "scope"=>"Node"}},
       "state"=>"unknown"},
     "eth0"=>
      {"type"=>"eth",
       "number"=>"0",
       "mtu"=>"1500",
       "flags"=>["BROADCAST", "MULTICAST", "UP", "LOWER_UP"],
       "encapsulation"=>"Ethernet",
       "addresses"=>
        {"00:0C:29:1A:64:6A"=>{"family"=>"lladdr"},
         "10.0.128.26"=>
          {"family"=>"inet",
           "prefixlen"=>"24",
           "netmask"=>"255.255.255.0",
           "broadcast"=>"10.0.128.255",
           "scope"=>"Global"}},
       "state"=>"up",
       "arp"=>
        {"10.0.128.31"=>"00:0c:29:04:12:9a",
         "10.0.128.100"=>"00:0c:29:5b:b4:46",
         "10.0.128.30"=>"00:0c:29:05:a4:c7",
         "10.0.128.18"=>"00:0c:29:6a:3f:75",
         "10.0.128.3"=>"0c:c4:7a:c0:31:d1",
         "10.0.128.43"=>"00:0c:29:01:eb:6b",
         "10.0.128.44"=>"00:09:0f:09:00:03",
         "10.0.128.14"=>"00:0c:29:d2:15:80",
         "10.0.128.22"=>"00:0c:29:18:99:30"},
       "routes"=>
        [{"destination"=>"10.0.128.0/24",
          "family"=>"inet",
          "scope"=>"link",
          "proto"=>"kernel",
          "src"=>"10.0.128.26"}],
       "link_speed"=>10000,
       "duplex"=>"Full",
       "port"=>"Twisted Pair",
       "transceiver"=>"internal",
       "auto_negotiation"=>"off",
       "mdi_x"=>"Unknown",
       "ring_params"=>
        {"max_rx"=>4096,
         "max_rx_mini"=>0,
         "max_rx_jumbo"=>2048,
         "max_tx"=>4096,
         "current_rx"=>256,
         "current_rx_mini"=>0,
         "current_rx_jumbo"=>128,
         "current_tx"=>512}},
     "eth1"=>
      {"type"=>"eth",
       "number"=>"1",
       "mtu"=>"1500",
       "flags"=>["BROADCAST", "MULTICAST", "UP", "LOWER_UP"],
       "encapsulation"=>"Ethernet",
       "addresses"=>
        {"00:0C:29:1A:64:74"=>{"family"=>"lladdr"},
         "11.11.11.1"=>
          {"family"=>"inet",
           "prefixlen"=>"24",
           "netmask"=>"255.255.255.0",
           "broadcast"=>"11.11.11.1",
           "scope"=>"Global"}},
       "state"=>"up",
       "routes"=>
        [{"destination"=>"default", "family"=>"inet", "via"=>"11.11.11.1"},
         {"destination"=>"11.11.11.1/24",
          "family"=>"inet",
          "scope"=>"link",
          "proto"=>"kernel",
          "src"=>"11.11.11.1"}],
       "link_speed"=>10000,
       "duplex"=>"Full",
       "port"=>"Twisted Pair",
       "transceiver"=>"internal",
       "auto_negotiation"=>"off",
       "mdi_x"=>"Unknown",
       "ring_params"=>
        {"max_rx"=>4096,
         "max_rx_mini"=>0,
         "max_rx_jumbo"=>2048,
         "max_tx"=>4096,
         "current_rx"=>256,
         "current_rx_mini"=>0,
         "current_rx_jumbo"=>128,
         "current_tx"=>512}}}

Answer 1

由于您对顶级密钥感兴趣，您可以这样做：

hash.find{ |k,v| break k if v.to_s.include? "10.0.128.26" }
#=> eth0

通过使用v.to_s，我们可以在哈希的字符串表示中进行搜索，也可以避免递归。

Answer 2

如果您想返回顶级父键，您可以使用顶级哈希键的 mentioned answer 和 find 以简单的方式完成

#return true if find or nil
def deep_key?(obj, key)
  if obj.respond_to?(:key?) && obj.key?(key)
    true
  elsif obj.respond_to?(:each)
    r = nil
    obj.find{ |*a| r = deep_key?(a.last, key) }
    r
  end
end

key = '00:0C:29:1A:64:74'

#now you check if the provided key is a top level key or run search
h.key?(key) ? key : h.find { |k, v| deep_key?(v, key) }.first

deep_key? 是对上述答案的一点修改的搜索功能，如果找到一个键，则返回 true（如果没有找到，则返回 nil）。您可以在 Hash#find 块内使用此函数 - 顶级键，如果找到他的值将是结果（添加 first 只返回一个键）。