VBA Highlight different duplicates with different colors across a table array - excel

Question

My question is in the title. I have searched up everywhere and this one feels like the only answer that is working:
https://stackoverflow.com/a/15180079/17038705
I have created a sample Excel file and validated that his VBA code works, the sample he shows looks like it is working too. However, when I ran it with the Excel file I am working on, I got Error 91, Object variable or With block variable not set.
After some digging, it is probably because of his Find() function that returns Nothing.
My question is why this is the case for my file and not for others. The values there are based on formulas and values of other cells, would that be a problem?
Other approaches are appreciated as well. Thanks!

Answer 1

Since your data contains formulas, you need to set the LookIn parameter to xlValues in the Find method. I updated the original code with these changes, take a look:
Sub Highlight_Duplicate_Entry()
Dim ws As Worksheet
Dim cell As Range
Dim myrng As Range
Dim clr As Long
Dim lastCell As Range
Set ws = ThisWorkbook.Sheets("Sheet1")
Set myrng = ws.Range("A2:D" & Range("A" & ws.Rows.Count).End(xlUp).Row)
With myrng
Set lastCell = .Cells(.Cells.Count)
End With
myrng.Interior.ColorIndex = xlNone
clr = 3
For Each cell In myrng
If Application.WorksheetFunction.CountIf(myrng, cell) > 1 Then
' addresses will match for first instance of value in range
'[================]
If myrng.Find(what:=cell, LookIn:=xlValues, lookat:=xlWhole, MatchCase:=False, after:=lastCell).Address = cell.Address Then
' set the color for this value (will be used throughout the range)
cell.Interior.ColorIndex = clr
clr = clr + 1
Else
' if not the first instance, set color to match the first instance
'[================]
cell.Interior.ColorIndex = myrng.Find(what:=cell, LookIn:=xlValues, lookat:=xlWhole, MatchCase:=False, after:=lastCell).Interior.ColorIndex
End If
End If
Next
End Sub

Answer 2

A slightly different approach using a Dictionary to track values vs. colors:
Sub Tester()
ColorDups Range("A1").CurrentRegion
End Sub
Sub ColorDups(rng As Range)
Dim c As Range, dict As Object, i As Long, v
Set dict = CreateObject("scripting.dictionary")
i = 0
Application.ScreenUpdating = False
For Each c In rng.Cells
v = CStr(c.Value)
If Len(v) > 0 Then
If Not dict.exists(v) Then
dict.Add v, c 'store the first cell with this value
Else
If TypeOf dict(v) Is Range Then 'second cell with this value?
i = i + 1 'next index
dict(v).Interior.ColorIndex = i 'color the first cell
dict(v) = i 'store the index
End If
c.Interior.ColorIndex = dict(v) 'color this duplicate
End If
End If
Next c
End Sub