How to handle negative lookbehind in Excel VBA regex?

The Excel VBA code is using a regular expression to extract section numbers from HTML files. However, the regex includes a negative lookbehind which is not supported in VBA regex. "(?<!tbl"")>(\d(\.\d)+)<"

Sub GetAllSectionNumbers()
    LRb = Cells(Rows.Count, "B").End(xlUp).Row
    Range("B7:C" & LRb).ClearContents
    Dim fileDialog As fileDialog
    Set fileDialog = Application.fileDialog(msoFileDialogOpen)
    
    fileDialog.AllowMultiSelect = True
    fileDialog.Title = "Select HTML files"
    fileDialog.Filters.Clear
    fileDialog.Filters.Add "HTML files", "*.htm;*.html", 1
    
    If fileDialog.Show <> -1 Then Exit Sub
    
    Dim file As Variant
    For Each file In fileDialog.SelectedItems
        Dim fileContents As String
        Open file For Input As #1
        fileContents = Input$(LOF(1), 1)
        Close #1
        
        Dim regex As Object
        Set regex = CreateObject("VBScript.RegExp")
        regex.Pattern = "(?<!tbl"")>(\d(\.\d)+)<"
        regex.Global = True
        regex.IgnoreCase = True
        regex.MultiLine = True
        TRET = regex.Pattern
        filePath = file
        fileFolder = Left(filePath, InStrRev(filePath, "\"))
        fileNameSource = Mid(filePath, InStrRev(filePath, "\") + 1, 100)
    
        Dim match As Object
        Set match = regex.Execute(fileContents)
        
        Dim i As Long
        For i = 0 To match.Count - 1
            LRb = Cells(Rows.Count, "B").End(xlUp).Row + 1
    
            Range("B" & LRb).Value = match.Item(i).SubMatches(0)
            Range("C" & LRb).Value = fileNameSource
        Next i
    Next file
    MsgBox "Done!"
End Sub

Is there an alternative regex solution for handling this?

>Solution :

As you are extracting, the traditional approach is to use the "best regex trick" that consists in matching what you do not need and matching and capturing what you need.

The regex in this specific situation will look like

tbl">\d(?:\.\d)+<|>(\d(?:\.\d)+)<

In the code, it will look like

regex.Pattern = "tbl"">\d(?:\.\d)+<|>(\d(?:\.\d)+)<"

Next, in your code, you should check if the match.SubMatches(0) value is actually present, and if yes, take it since it is what you need.

See the regex demo.