如何使用LINQ分組和合並數據列表？

Question

我有數據列表如下圖所示

原始數據

Genre Name      Year 
Comedy Shrek Forever After  2010 
Drama The Karate Kid    2010 
Action Iron Man 2     2010 
Action Robin Hood     2010 
Drama The Kids Are All Right  2010 
Sci-Fi Inception     2010 

，我需要按流派的電影和串聯類似電影的名字由「」分隔，因此新列表如下像

所需的數據

Genre Name          Year 
Comedy Shrek Forever After      2010 
Drama The Karate Kid, The Kids Are All Right 2010 
Action Iron Man 2, Robin Hood     2010 
Sci-Fi Inception        2010 

的LINQ語句我寫的是如下

Dim result = From p In movies Group p By p.Genre Into Group Select New Movie With { 
     .Genre = Genre, 
     .Name = String.Join(", ", Group.Select(Function(p) p.Name).ToArray()), 
     .Year = Group.Select(Function(p) p.Year).FirstOrDefault 
     } 

有沒有的做，這樣我就不必用另一種方式」 .Year = Group.Select（功能（P）p.Year） .FirstOrDefault「或者與我的方法不同。

感謝

示例代碼：

---

Module Module1 

    Sub Main() 
     Dim movies As New List(Of Movie) 
     movies.Add(New Movie("Comedy", "Shrek Forever After", 2010)) 
     movies.Add(New Movie("Drama", "The Karate Kid", 2010)) 
     movies.Add(New Movie("Action", "Iron Man 2", 2010)) 
     movies.Add(New Movie("Action", "Robin Hood", 2010)) 
     movies.Add(New Movie("Drama", "The Kids Are All Right", 2010)) 
     movies.Add(New Movie("Sci-Fi", "Inception", 2010)) 

     'Group amd Merge by genre 
     Dim result = From p In movies Group p By p.Genre Into Group Select New Movie With { 
     .Genre = Genre, 
     .Name = String.Join(", ", Group.Select(Function(p) p.Name).ToArray()), 
     .Year = Group.Select(Function(p) p.Year).FirstOrDefault 
     } 

     For Each r In result 
      Console.WriteLine(r) 
     Next 
     Console.ReadKey() 
    End Sub 

    Public Class Movie 
     Public Genre As String 
     Public Name As String 
     Public Year As Integer 

     Public Sub New() 
     End Sub 

     Public Sub New(ByVal genre As String, ByVal name As String, ByVal year As Integer) 
      Me.Year = year 
      Me.Genre = genre 
      Me.Name = name 
     End Sub 

     Public Overrides Function ToString() As String 
      Return String.Format("Genre: {0}; Name:{1}; Year:{2}", Genre, Name, Year) 
     End Function 
    End Class 

End Module 

Answer 1

如果你確保Year永遠不會爲空，這基於你的類不應該是，你可以取代它與此：

.Year = Group.First().Year 

但是，我質疑你的分組方法。當具有相同類型的電影不共享同一年時會發生什麼？一個可能是2009年，另一個2010年，你會自動拿到第一年。您可以添加OrderBy以獲取最近的一年，但這一切都取決於您的分組意圖。