如何使用Newtonsoft查询嵌套JToken数组，获取按Severity降序的前10个对象

我有一个由JToken对象组成的嵌套数组，目前只能返回所有Severity<3的问题，但我希望获取按Severity成员降序排列的前10个对象。现在我在访问内层数组时遇到了困难，能不能指导我用Newtonsoft查询数据实现这个需求？

示例数据 #

[
  [
    {
      "IssueOrderNumber": 1,
      "Description": "Exhaust fumes leaking into Parts department.",
      "Resolution": "Increased outbound ventilation in Service area.",
      "Severity": 1
    }
  ],
  [
    {
      "IssueOrderNumber": 1,
      "Description": "Houston, we have a problem.",
      "Resolution": "We are working on it.",
      "Severity": 1
    },
    {
      "IssueOrderNumber": 2,
      "Description": "We have issues with employee retention.",
      "Resolution": "We will start giving retention bonuses.",
      "Severity": 2
    },
    {
      "IssueOrderNumber": 3,
      "Description": "Increasing incidents of sexual harassment.",
      "Resolution": "Sexual harassment training is now doubled, and an independent investigator/arbitrator has been hired.",
      "Severity": 2
    }
  ],
  [
    {
      "IssueOrderNumber": 1,
      "Description": "Deal worksheet left unattended on salesperson's desk",
      "Resolution": "Salesperson required training hours doubled",
      "Severity": 2
    },
    {
      "IssueOrderNumber": 2,
      "Description": "PII left exposed for customers submitting inquiries over Web",
      "Resolution": "Web site reengineered to encrypt PII",
      "Severity": 2
    },
    {
      "IssueOrderNumber": 3,
      "Description": "A hacker exposed PII for sales staff and managerial staff over the Web.",
      "Resolution": "Web site was patched",
      "Severity": 1
    }
  ]
]

现有代码 #

jArrIssues2 = JArray.Parse(strJArrIssues);
for (int i = 0; i < jArrIssues2.Count; i++)
{
    for (int j = 0; j < jArrIssues2[i].Count(); j++)
    { 
        JObject iss = JObject.Parse(jArrIssues2[i][j].ToString());
        JObject tmpObj = new JObject();
        int intSev = (int)iss["Severity"];
        string strDescr = (string)iss["Description"];
        if (intSev < 3) // Currently, getting all Sev 1, 2 issues;
                        // I'd rather get the top 10 issues ordered by severity
        { 
            tmpObj.AddFirst(new JProperty("Description", strDescr));
            tmpObj.Property("Description").AddAfterSelf(new JProperty("Severity", intSev));
            jArrUltimate.Add(tmpObj);
        }
    }
}

可以利用LINQ结合Newtonsoft.Json的API简化操作，无需嵌套循环，直接完成扁平化、筛选、排序和取前10的操作：

JArray jArrIssues2 = JArray.Parse(strJArrIssues);

// 扁平化嵌套数组，筛选Severity<3的项，按Severity降序排列，取前10
var topIssues = jArrIssues2
    // 展开外层数组的所有内层数组，得到单个JToken对象集合
    .SelectMany(innerArray => innerArray)
    // 转换为JObject方便属性访问
    .Select(token => token as JObject)
    // 过滤有效项：非空且Severity<3
    .Where(issue => issue != null && (int)issue["Severity"] < 3)
    // 按Severity降序排序，若需进一步排序可追加条件（如IssueOrderNumber）
    .OrderByDescending(issue => (int)issue["Severity"])
    // 取前10个结果
    .Take(10)
    // 构造仅包含目标属性的JObject
    .Select(issue => new JObject(
        new JProperty("Description", (string)issue["Description"]),
        new JProperty("Severity", (int)issue["Severity"])
    ))
    // 转换为JArray
    .ToArray();

JArray jArrUltimate = new JArray(topIssues);

代码说明 #

• SelectMany：直接扁平化嵌套数组，避免手动嵌套循环遍历内层元素。
• 类型转换与筛选：将JToken转为JObject，过滤出符合Severity<3的有效问题项。
• 排序与截取：通过OrderByDescending实现降序排序，Take(10)直接获取前10个结果。
• 结果构造：按需保留Description和Severity属性，最终组装成目标JArray。

这种写法比原始嵌套循环更简洁高效，也符合C#的LINQ编程风格。

内容的提问来源于stack exchange，提问作者Nosnetrom