从字典

Question

我没有找到一种优雅的Linq方式来检索分配给人员列表中的人员的最大日期，这些人员被分配到任务中。

我的代码是

public class Mission
{
    public string MissonAssignedTo { get; set; }
    public DateTime Date { get; set; }
}

public Dictionary<string, Dictionary<string, List<Mission>>> MissionList = 
    new Dictionary<string, Dictionary<string, List<Mission>>>();

我有这种价值的字典

MissionList[0] Key = MissionImpossible
            Value = count 1
                  Key=Sean
                  Value=count 7
                        [0] = date = 10/01/2017
                        [1] = date = 10/01/2016
                        [2] = date = 10/01/2017
                        [3] = date = 10/01/2018
                        [4] = date = 10/01/2015
                        [5] = date = 10/01/2014
                        [6] = date = 10/01/2013

MissionList[1] Key = MissionImpossibleThePayPack
            Value = count 1
                  Key=Connery
                  Value=count 4
                        [0] = date = 10/01/2017
                        [1] = date = 10/01/2019
                        [2] = date = 10/01/2017
                        [3] = date = 10/01/2018

我需要为每个人和他的最大日期检索字典，就像这样。

dicoResult= { 
                {Sean,10/01/2018} , 
                {Connery,10/01/2019} 
            }

祝你好运。 Jolynice

Answer 1

虽然您的自定义类型对我来说很奇怪，但如果我理解正确，那么这应该会给您预期的结果： -

var result = MissionList.SelectMany(x => x.Value)
                        .ToDictionary(x => x.Key, y => y.Value.Max(z => z.Date));

首先展平内部字典，然后使用ToDictionary将结果投影到字典中。

Sample Fiddle.