Binaryworld - Concatenate an array of strings with commas and a final "and", or othe ... [ VB.net -> String ]

' Concatenate an array of strings with commas and a final "and",
' or other separators
'
' Example:
' Debug.WriteLine("Choose one from " & CreateStringList(New String() {"item1",
' "item2", "item3"}))
' ' => Choose one from item1, item2 and item3

Function CreateStringList(ByVal items() As String, Optional ByVal sep As String _
  = ", ", Optional ByVal lastSep As String = " and ") As String
  ' join the strings with the first separator
  Dim res As String = String.Join(sep, items)
  ' find the last occurrence of the separator used to join the strings,
  ' remove it and insert the last separator instead
  Dim i As Integer = res.LastIndexOf(sep)
  If i > -1 Then
    res = res.Remove(i, sep.Length)
    res = res.Insert(i, lastSep)
  End If
  Return res
End Function