Function F0000(t As String) As String
Dim i%, flag As Boolean, fin%, deb%
For i = 1 To Len(t) + 1
If flag Then
If Not IsNumeric(Mid(t, i, 1)) Then fin = i: Exit For
Else
If IsNumeric(Mid(t, i, 1)) Then
flag = True
deb = i
End If
End If
Next
If deb Then F0000 = Left(t, deb - 1) & Format(Mid(t, deb, fin - deb), "0000") & Mid(t, fin) Else F0000 = t
End Function