Bonjour,
Avec un peu de retard, mais didactique
Cdlt
Option Explicit
Public Sub test()
Dim Ws As Worksheet
Dim derLigne As Long, i As Long
Application.ScreenUpdating = False
Set Ws = Worksheets("Feuil1")
With Ws
derLigne = .Range("A" & Rows.Count).End(xlUp).Row
For i = 1 To derLigne Step 1
If UCase(Left(.Cells(i, "A"), 1)) = "G" Then
.Cells(i, "B") = "ok"
Else
.Cells(i, "B") = "nok"
End If
Next i
End With
Set Ws = Nothing
End Sub