Question

我正在尝试学习如何使用Ruby解析JSON元素并且遇到了障碍。

在下面的代码片段中，categories项会返回数据但是如何访问它的子元素？例如，在JSON响应中，我想要仅获得类别的标签值。

JSON响应

{
    "title": "test",
    "updated": "2013-12-02T01:46:51.282Z",
    "startIndex": 1,
    "itemsPerPage": 1,
    "entries": [
        {
            "id": "fooURL",
            "title": "fooTitle",
            "updated": "2013-12-01T04:15:16Z",
            "published": "2013-11-30T21:49:58Z",
            "categories": [
                {
                    "term": "c706572879441004880dba7Fa5283c3e",
                    "scheme": "http://fooURL.com/id/",
                    "label": "Photo"
                },
                {
                    "term": "20DFCC087E4E10048925D0913B2D075C",
                    "scheme": "http://fooURL.com/id/",
                    "label": "NHL hockey "
                },
                {
                    "term": "20DE22407E4E100488FBD0913B2D075C",
                    "scheme": "http://fooURL.com/id/",
                    "label": "Professional hockey "
                }
            ]
        }
    ]
}

代码

    require "rubygems"
    require "json"
    require "net/http"
    require "uri"

    uri = URI.parse("http://fooURL.com/v2/search/photo?q=Giroux&count=2&apikey=mykey")

    http = Net::HTTP.new(uri.host, uri.port)
    request = Net::HTTP::Get.new(uri.request_uri, {'Accept' => 'application/json'})

    response = http.request(request)
    result = JSON.parse(response.body[3..-1].force_encoding("UTF-8"))[ "entries" ]


    result.each do |item| 
      puts item["id"]
      puts item["title"]
      puts item["updated"]
      puts item['categories']
    end

Answer 1

json = JSON.parse(str)
json['entries'].each { |entry|
  entry['categories'].each { |category|
    puts category['label']
  }
}

Answer 2

str = '{ "title": "test", "updated": "2013-12-02T01:46:51.282Z", "startIndex": 1, "itemsPerPage": 1, "entries": [ { "id": "fooURL", "title": "fooTitle", "updated": "2013-12-01T04:15:16Z", "published": "2013-11-30T21:49:58Z", "categories": [ { "term": "c706572879441004880dba7Fa5283c3e", "scheme": "http://fooURL.com/id/", "label": "Photo" }, { "term": "20DFCC087E4E10048925D0913B2D075C", "scheme": "http://fooURL.com/id/", "label": "NHL hockey " }, { "term": "20DE22407E4E100488FBD0913B2D075C", "scheme": "http://fooURL.com/id/", "label": "Professional hockey " } ] } ] }'

obj = JSON.parse(str)

obj['entries'][0]['categories'].map { |c| c['label'] }

最后一行给出了3元素的字符串数组

'Photo'
'NHL hockey'
'Professional hockey'

使用Ruby深入研究JSON

2 个答案: