LINQ分裂与生成性质的分组

Question

我有一个对象，对象的一个属性是逗号分隔的名称列表。

IList<Audits> auditData = new List<Audits>();
auditData.Add(new Audit
              {
                  Auditors = "Adam West, George Best",
                  TimeSpent = 7
              });

auditData.Add(new Audit
              {
                  Auditors = "Adam West",
                  TimeSpent = 5
              });

auditData.Add(new Audit
              {
                   Auditors = "Adam West, George Best, Elvis Presley",
                   TimeSpent = 3
              });

我想使用LINQ查询这些数据，拆分审计师属性，按审计师分组，并为每个审计师总计时间，给出一份审计员列表，列出针对每个审计员花费的时间。

亚当·韦斯特15

乔治·贝斯特10

猫王普雷斯利3

有人能帮我吗？谢谢。

Answer 1

这应该是你想做的事：

var query =
    from a in auditData
    let auditors = a.Auditors.Split(',').Select(s => s.Trim())
    from au in auditors
    group a.TimeSpent by au into g
    select new { Auditor = g.Key, TimeSpent = g.Sum() };

Answer 2

使用lambdas：

var results =
    auditData
        // Flatten list - to list of individual auditors and time spent
        .SelectMany(
            audit => audit.Auditors.Split(',').Select(s => s.Trim()),
            (audit, auditorName) => new
            {
                Auditor = auditorName,
                TimeSpent = audit.TimeSpent,
            })
        // Group by auditor name
        .GroupBy(a => a.Auditor)
        // Sum time spent
        .Select(auditorGroup => new
        {
            Auditor = auditorGroup.Key,
            TotalTimeSpent = auditorGroup.Sum(a => a.TimeSpent)
        })
        .ToList();

Answer 3

var res = auditData.Select(audit => audit.Auditors.Split(',').ToDictionary(a => a, a => audit.TimeSpent))
            .SelectMany(a => a)
            .GroupBy(a => a.Key)
            .ToDictionary(g => g.Key, s => s.Sum(g => g.Value));

首先拆分字符串并转换为KeyValue对。然后把字典压成一本。然后分组和和。