讀取數組vb.net中最後一個X行數

Question

我使用下面的代碼，但它給了我數組的前10行。我不知道如何獲得數組的10行。

 Dim t_low As String 

     Dim l_low() As String = low.Split(vbCrLf.ToCharArray, StringSplitOptions.RemoveEmptyEntries) 


     For c As Integer = 0 To l_low.Length - 1 
      If c <= 10 - 1 Then 
       t_low = t_low & l_low(c) & "," 
      End If 
     Next 
     MsgBox(t_low) 

Answer 1

試試這個：

Dim t_low_1 As String = "" 
Dim t_low_2 As String = "" 

Dim l_low() As String = low.Split(vbCrLf.ToCharArray, StringSplitOptions.RemoveEmptyEntries) 

For i As Integer = l_low.Length - 1 To l_low.Length - 10 Step -1 
    t_low_1 = t_low_1 & l_low(i) & IIf(i <> l_low.Length - 10, ",", "") 
    t_low_2 = l_low(i) & IIf(i <> l_low.Length - 1, ",", "") & t_low_2 
Next i 

MsgBox(t_low_1) 
MsgBox(t_low_2) 

我用了兩個variabile的（t_low_1和t_low_2），因爲我不明白你想要顯示結果的順序。

Answer 2

Dim t_low As String 

    Dim l_low() As String = low.Split(vbCrLf.ToCharArray, StringSplitOptions.RemoveEmptyEntries) 

    Array.Reverse(l_low) 

    For c As Integer = 0 To 9    
     t_low = t_low & l_low(c) & ","    
    Next 
    MsgBox(t_low) 

Answer 3

我有一些數量的項目的陣列（測試）。此代碼連接第一個和最後10個項目，用逗號分隔。

Dim s As New System.Text.StringBuilder 
    If test.Length >= 10 Then 
     'first 10 
     For c As Integer = 0 To 9 
      s.Append(test(c) & ",") 
     Next 
     'last 10 
     For c As Integer = test.Length - 10 To test.Length - 1 
      s.Append(test(c) & ",") 
     Next 
     s.Remove(s.Length - 1, 1) 'remove trailing comma 
     Debug.WriteLine(s.ToString) 
    End If 

Answer 4

使用LINQ：

Dim l_low() As String = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12"} 
Dim l_low2() As String = l_low.Skip(Math.Max(0, l_low.Length - 10)).Take(10).ToArray 

然後，您可以加入使用String.Join逗號分隔起來的l_low2元素。