поля доступа vb.net после line.split

Question

Я хочу изменить/чек х (5), используя, если заявление
если х (5) = 270, то х (5) = -90
Есть ли способ доступ к массиву.

Sub Main() 
    Dim filePath, filePathOut As String 
    Dim fileName As String 
    fileName = "test.txt" 
    filePath = System.IO.Path.Combine(My.Computer.FileSystem.SpecialDirectories.MyDocuments, fileName) 
    filePathOut = System.IO.Path.Combine(My.Computer.FileSystem.SpecialDirectories.MyDocuments, "out\" & fileName) 
    ' Create the IEnumerable data source. 
    Dim lines As String() = System.IO.File.ReadAllLines(filePath) 


    Dim lineQuery = From line In lines 
        Let x = line.Split(New Char() {","}) 
        Order By x(0) 
        Select x(0) & ", " & x(3) & ", " & x(5) 

    System.IO.File.WriteAllLines(filePathOut, lineQuery.ToArray()) 

    Console.WriteLine("Spreadsheet2.csv written to disk. Press any key to exit") 
    Console.ReadKey() 
End Sub 

Answer 1

Вы имели в виду условное выражение для третьей столбцы CSV, что-то вроде этого?

Dim lineQuery = From line In lines 
       Let x = line.Split(New Char() {","}) 
       Order By x(0) 
       Select x(0) & ", " & x(3) & ", " & If(x(5) = "270", "-90", x(5)) 

Справочно: Is there a conditional ternary operator in VB.NET?

Answer 2

Возможно, что-то подобное будет работать.

Dim lineQuery = From line In lines 
        Let x = line.Split(New Char() {","}) 
        Order By x(0) 
        Where x(5) = 270 
        Select x(5) = -90 And x(0) & ", " & x(3) & ", " & x(5) 

Более подробный ответ можно найти here.

Answer 3

Одна вещь, чтобы рассмотреть с текущим методом с использованием LINQ, если есть строки, которые не соответствуют вашим ожидаемым данным в текстовом файле. При этом следующие проблемы допускают, например, проблемы. строка не имеет ожидаемого количества столбцов или строка пуста.

Существует больше кода, чем однострочный оператор lambda или linq, но как указано выше, чтобы разрешить использование утверждения.

Imports Microsoft.VisualBasic.FileIO 
Public Class Form2 

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 

     Dim readFile As String = 
      IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Textfile1.txt") 

     Dim writeFile As String = 
      IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Textfile2.txt") 

     Dim Lines As New List(Of Line) 

     Using reader As New TextFieldParser(readFile) 

      reader.TextFieldType = FieldType.Delimited 
      reader.Delimiters = New String() {","c} 

      Dim currentRow As String() 

      While Not reader.EndOfData 
       ' 
       ' Feel free to discard the try/catch if so be it 
       ' 
       Try 
        currentRow = reader.ReadFields() 
        Lines.Add(New Line(currentRow)) 

       Catch ex As MalformedLineException 
        ' decide how to handle 
       End Try 
      End While 
     End Using 

     IO.File.WriteAllLines(writeFile, 
      Lines.OrderBy(Function(item) item.Column0) _ 
      .Select(Function(item) item.ItemArray).ToArray) 

    End Sub 
End Class 
''' <summary> 
''' Used to create a line item that will 
''' be inserted into a List(Of Line) in the caller 
''' reading a text file. 
''' </summary> 
''' <remarks> 
''' Gave generic names to properties, we could do an 
''' an anonymous type inside of Lambda or Linq and done 
''' away with the class but felt this is simply another 
''' option 
''' </remarks> 
Public Class Line 
    Public Property Column0 As String 
    Public Property Column1 As String 
    Public Property Column2 As String 
    Public Property Column3 As String 
    Public Property Column4 As String 
    Public Property Column5 As String 
    Public Sub New(ByVal sender As String()) 
     If sender.Length = 6 Then 
      Column0 = sender(0) 
      Column1 = sender(1) 
      Column2 = sender(2) 
      Column3 = sender(3) 
      Column4 = sender(4) 
      If sender(5) = "270" Then 
       Column5 = "-90" 
      Else 
       Column5 = "270" 
      End If 
     Else 
      ' decide how to handle incorrect columns in a line 
     End If 
    End Sub 
    Public Function ItemArray() As String 
     Return String.Format("{0},{1},{2},{3},{4},{5}", 
      Column0, Column1, Column2, Column3, Column4, Column5) 
    End Function 
End Class