特定字典键C＃的计数值

Question

我必须计算特定键处字典的值。 我的代码是：

foreach (CurrentCluster curCluster in curClusters){
   twObjClus.WriteLine("Cluster_ID: {0} - Cluster_Size: {1} \n",  
   curCluster.GetClusterID(), curCluster.GetClusterSize());
   twObjClus.WriteLine("------------------------------------------------------------");
    foreach (EvoObject eEvoObject in curCluster.GetClusterObjects()){
        Author eAuthor = (Author)eEvoObject.GetOriginalObject(); 

        twObjClus.WriteLine("\n");
        twObjClus.WriteLine(@"Author_ID: {0}, Author_Name: {1} ",  
        eAuthor.AuthorID, eAuthor.AuthorName);
        twObjClus.WriteLine("----------------------------------------------------------");

        Dictionary<int, Tuple<int, int>> tPapers =  
        eAuthor.GetPapersBetweenYears(year, year + 1);
        List<int> tCoAuthors =  
        eAuthor.GetCoAuthorsBetweenYears(year, year + 1);
        List<int> tVenues = eAuthor.GetVenuesBetweenYears(year, year + 1);
        foreach (var kvpaper in tPapers){
           // Key is Paper_ID, Item1 is Paper_Category, Item2 is Year
           twObjClus.WriteLine("PaperID: {0}, PaperCategory: {1}, Year: {2}",  
           kvpaper.Key, kvpaper.Value.Item1, kvpaper.Value.Item2);
        }
        foreach (var kvCoAuthor in tCoAuthors){
           twObjClus.WriteLine("CoAuthorID: {0}", kvCoAuthor);
        }
        foreach (var kvVenue in tVenues){
           twObjClus.WriteLine("VenueID: {0}", kvVenue);
        }
    } 
    twObjClus.WriteLine("\n\n");
}
twObjClus.Flush();    twObjClus.Close();

现在，我想计算Paper_Category每个不同值，即Dictionary Paper_Category Tuple Item1 。

次要细节
这实际上是我要从数据中获取结果的聚类。 由于每个群集将具有与某些对象关联的Paper_Category数量。 我想要的是对每个类别进行计数，并将该群集存储为单个类别，即计数最高的类别。

如果eAuthor是一个列表，并且我必须检查所有eAuthor最高的Paper_Category计数，并且每个eAuthor也可能包含几个Paper_Category ，那么该如何计数？

如何计算Paper_Category每个值的Paper_Category并将其写为文本？

Answer 1

var categoryGroups = tPapers.Values.GroupBy(t => t.Item1);

foreach(var g in categoryGroups)
    Console.WriteLine("Category:{0} Count:{1}", g.Key, g.Count());

如何选择或存储计数最高的类别（在变量中）？

var highestCount =  categoryGroups.OrderByDescending(g => g.Count())
     .Select(g => new { Category = g.Key, Count = g.Count() })
     .First();
Console.WriteLine("Category:{0} Count:{1}", highestCount.Category, highestCount.Count);

---

由于您想获取eAuthor所有作者的论文类别计数，并且这似乎是您的课程，因此请使用SelectMany ：

var categoryGroups = eAuthor
    .SelectMany(a => a._Papers.Select(p => p._PaperCategory))
    .GroupBy(pc => pc);
// rest is same

Answer 2

正如您在评论中提到的，使用linq来获得最高收益：

int? highestCat = tPapers.Values.GroupBy(p => p.Item1)
                .OrderByDescending(x => x.Count())
                .FirstOrDefault()?.Key;

Console.WriteLine($"Highest Paper_Category is: { highestCat }");