MS Access VBA Functions (Part 2) Address Matching – UK Postcode String Finder

UK Postcode extractor

Function GetPostCode(Optional AddressText As Variant) As String
Dim AddrTextLength As Integer, TempText As String, TempPicture As String
Dim PostCodePics(10) As String, PictureItemNum As Integer
Dim n As Integer, x As Integer

GetPostCode = "" ' default response if no postcode detected
If IsNull(AddressText) Then
Exit Function
End If

PostCodePics(1) = "XXNSNXX" ' alternative formats of postcodes
PostCodePics(2) = "XXNNSNXX" ' where X = alpha, S = space
PostCodePics(3) = "XNNSNXX" ' and N = numeric
PostCodePics(4) = "XNSNXX"
PostCodePics(5) = "XXNNXX"
PostCodePics(6) = "XXNNNXX"
PostCodePics(7) = "XNNNXX"
PostCodePics(8) = "XNNXX"
PostCodePics(9) = "XXNXNXX"
PostCodePics(10) = "XXNXSNXX"

AddrTextLength = Len(AddressText)

If AddrTextLength < 5 Then
Exit Function
End If
If AddrTextLength <= 9 Then
TempText = Trim(AddressText)
Else
TempText = Trim(Right(AddressText, 9))
End If

PictureItemNum = 0
TempPicture = "" ' build a picture of the format of current text
For n = 1 To Len(TempText) ' detect the type of each character
x = InStr(1, "1234567890 ", Mid(TempText, n, 1))
If x > 0 And x < 11 Then TempPicture = TempPicture & "N"
If x = 11 Then TempPicture = TempPicture & "S"
If x = 0 Then TempPicture = TempPicture & "X"
Next

For n = 1 To 10 ' compare the format of the current text
x = Len(PostCodePics(n)) ' against each of the post code pictures
If Len(TempPicture) >= x Then
If Right(TempPicture, x) = PostCodePics(n) Then
PictureItemNum = n
GetPostCode = UCase(Right(TempText, x))
Exit For
End If
End If
Next

If PictureItemNum > 4 And PictureItemNum < 10 Then ' insert space in the middle if not present
GetPostCode = Left(GetPostCode, Len(GetPostCode) - 3) & " " & Right(GetPostCode, 3)
End If

End Function

Author: Mark

Mark Brooks a forty something individual working and living in and around Edinburgh