Visual Basic LINQ

Question

我有两个文件，一个参议员谁退休和完整的参议员之一。我需要从完整名单中删除退休的参议员。我正在使用LINQ来处理这个问题，因为我不能像我期望的那样工作。我试图将一个查询与另一个查询进行比较，只将参议员从当前名单中退出，然后将他们添加到新文件中。但是当我打开新文件时，它并没有删除退休的参议员。这里是我的代码感谢提前任何帮助。

 ' Query for retired senators 
    Dim senateRetiered = From line In retieredSen 
         Let data = line.Split(","c) 
         Let retName = data(0) 
         Select retName 

    ' query length 
    Dim index As Integer = senateRetiered.ToArray.Length 

     ' Add one to our index we will remove it later in our next query 
    index += 1 

    ' Query for or 110th senate compare to our other query and only select senators that have not retiered 
    Dim senate110Query = From line In senate110 
         Let data = line.Split(","c) 
         Let name = data(0) 
         Let state = data(1) 
         Let party = data(2) 
         Where name <> senateRetiered(index - 1) 
         Select line 

     ' Write the remaining sentators to a new file 
    IO.File.WriteAllLines("sortedSentate.txt", senate110Query) 

Answer 1

我不知道我真正理解你的问题，但我认为第二个查询应该看起来更像是：

Dim senate110Query = From line In senate110 
        Let data = line.Split(","c) 
        Let name = data(0) 
        Let state = data(1) 
        Let party = data(2) 
        Where Not senateRetired.Any(Function(r) r.Name = name) 
        Select line 

Answer 2

我有一个替代的解决方案是较为复杂;然而，它使参议员成为阶级。如果你需要做的除了文件创建参议员一些其他的工作，它可能是有用的

Class Senator 
    Public Name As String 
    Public State As String 
    Public Party As String 

    Public Overrides Function Equals(ByVal obj As Object) As Boolean 
     Dim other = TryCast(obj, Senator) 
     If other Is Nothing Then 
      Return False 
     End If 
     Return Name.Equals(other.Name) 
    End Function 

    Public Overrides Function ToString() As String 
     Return String.Format("{0},{1},{2}", Name, State, Party) 
    End Function 
End Class 

有了这个声明，你可以做到这一点

Dim senateRetiered = From line In retieredSen _ 
Let data = line.Split(","c) _ 
Select New Senator() With {.Name = data(0)} 

Dim senate110Query = From line In senate110 _ 
Let data = line.Split(","c) _ 
Select New Senator() With {.Name = data(0), .State = data(1), .Party = data(2)} 

Dim nonRetired = senate110Query.Except(senateRetiered) 

Dim nonRetiredString = nonRetired _ 
.Select(Function(sen) sen.ToString()) 
'Note: I have to append a ".ToArray()" with .NET 3.5 

IO.File.WriteAllLines("sortedSentate.txt", nonRetiredString)