In sentences like:
\"[x] Alpha
[33] Beta\"
I extract an array of bracketed data as ([x], [33])
using VBA regex Pattern:
\"(\\
With Excel and VBA you can strip the brackets after the regex extraction:
Sub qwerty()
Dim inpt As String, outpt As String
Dim MColl As MatchCollection, temp2 As String
Dim regex As RegExp, L As Long
inpt = "38c6v5hrk[x]537fhvvb"
Set regex = New RegExp
regex.Pattern = "(\[x\])|(\[\d*\])"
Set MColl = regex.Execute(inpt)
temp2 = MColl(0).Value
L = Len(temp2) - 2
outpt = Mid(temp2, 2, L)
MsgBox inpt & vbCrLf & outpt
End Sub