Test for duplicates on partial cell contents in a column in Excel 2003/XP/2000/97

Question: In Excel 2003/XP/2000/97, is it possible to write a macro which would highlight any duplicate values in column A? My problem is that sometimes the cell values do not match exactly.

For example, cell A1 contains "1234" and cell A2 contains "1234, 5678". Is there a way to compare partial cell contents so that a duplicate entry flag would be set for cells A1 and A2 in this example?

Answer: Let's take a look at an example.

In our spreadsheet, we've set up column A to contain unique values. On this sheet, we've created a button that when clicked will launch a macro. This macro will highlight any duplicate values in column A.

In our example, we've clicked on the button. Now the background color of the partial duplicates will turn red as follows:

In this example, the partial value of 1234 has been entered in cells A2, A5, and A6.

You can press Alt-F11 to view the VBA code.

Please note that the LRows variable in this macro is set to 200 indicating that the macro will test the first 200 rows in column A for duplicates. You may need to change this value to accommodate your volume of data.



Macro Code:
The macro code looks like this:

Sub TestForDups()

Dim LLoop As Integer
Dim LTestLoop As Integer
Dim LClearRange As String

Dim Lrows As Integer
Dim LRange As String
Dim LChangedValue As String
Dim LTestValue As String

'Test first 200 rows in spreadsheet for uniqueness
Lrows = 200
LLoop = 2

'Clear all flags
LClearRange = "A2:A" & Lrows
Range(LClearRange).Interior.ColorIndex = xlNone

'Check first 200 rows in spreadsheet
While LLoop <= Lrows
LChangedValue = "A" & CStr(LLoop)

If Len(Range(LChangedValue).Value) > 0 Then

'Test each value for uniqueness
LTestLoop = 2
While LTestLoop <= Lrows
If LLoop <> LTestLoop Then
LTestValue = "A" & CStr(LTestLoop)
'Value has been duplicated in another cell
If InStr(Range(LTestValue).Value, Range(LChangedValue).Value) > 0 Then
'Set the background color to red
Range(LChangedValue).Interior.ColorIndex = 3
Range(LTestValue).Interior.ColorIndex = 3

End If

End If

LTestLoop = LTestLoop + 1

Wend

End If

LLoop = LLoop + 1
Wend

End Sub