vba - 如何读取文本文件中的倒数第二行

Question

我想在 VBA 中读取一个大文件并在线看到此代码:

Dim MyChar As String, Pointer As Long, LastLine As String
Open "MyTextFile.Txt" For Binary As #1
Pointer = LOF(1) - 2
MyChar = Chr$(32)
Do
    Get #1, Pointer, MyChar
    If MyChar = vbCr Or MyChar = vbLf Then
        Exit Do
    Else: Pointer = Pointer - 1
        LastLine = MyChar & LastLine
    End If
Loop
MsgBox "Last Line is " & LastLine

如何更改此代码以获取倒数第二行？在这方面需要一些帮助。

想到了这个:

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objTextFile = objFSO.OpenTextFile _
    "MyTextFile.Txt", 1)
objTextFile.ReadAll
MsgBox objTextFile.Line

但我无法到达 2 号线。

Answer 1

您提供的代码如下:

它设置一个指向文件的最后一个字符的指针

然后它向后读取该文件，直到找到换行符

它返回所有读取的内容作为最后一行。

为了根据您的需要修改它，我添加了 Boolean secondRun ，这让代码再次运行第 2 步，从而记录最后第二行:

Dim MyChar As String, Pointer As Long, LastLine As String
Open "MyTextFile.Txt" For Binary As #1
Pointer = LOF(1) - 2
MyChar = Chr$(32)
Dim secondRun As Boolean
Do
    ' Read character at position "Pointer" into variable "MyChar"
    Get #1, Pointer, MyChar
    If MyChar = vbCr Or MyChar = vbLf Then  ' Linebreak = line read completely
        If Not secondRun Then
            ' Run again if we've read only one line so far
            secondRun = True
            LastLine = ""
            Pointer = Pointer - 2
        Else
            Exit Do
        End If
    Else: Pointer = Pointer - 1
        ' Add character to result String
        LastLine = MyChar & LastLine
    End If
Loop
MsgBox " 2nd last line is " & LastLine