excel vba test or check if sheet exists
'VBA function to test if a sheet exists in the active workbook:
Function IsSheet(n$) As Boolean
IsSheet = Not IsError(Evaluate(n & "!a1"))
End Function
'-----------------------------------------------------------------------
'Same thing, different technique (much faster):
Function IsSheet(n$) As Boolean
On Error Resume Next
IsSheet = Sheets(n).Index
End Function