excel-vba Locating duplicate values in a range Find duplicates in a range
Example
The following tests range A2 to A7 for duplicate values. Remark: This example illustrates a possible solution as a first approach to a solution. It's faster to use an array than a range and one could use collections or dictionaries or xml methods to check for duplicates.
Sub find_duplicates()
' Declare variables
Dim ws As Worksheet ' worksheet
Dim cell As Range ' cell within worksheet range
Dim n As Integer ' highest row number
Dim bFound As Boolean ' boolean flag, if duplicate is found
Dim sFound As String: sFound = "|" ' found duplicates
Dim s As String ' message string
Dim s2 As String ' partial message string
' Set Sheet to memory
Set ws = ThisWorkbook.Sheets("Duplicates")
' loop thru FULLY QUALIFIED REFERENCE
For Each cell In ws.Range("A2:A7")
bFound = False: s2 = "" ' start each cell with empty values
' Check if first occurrence of this value as duplicate to avoid further searches
If InStr(sFound, "|" & cell & "|") = 0 Then
For n = cell.Row + 1 To 7 ' iterate starting point to avoid REDUNDANT SEARCH
If cell = ws.Range("A" & n).Value Then
If cell.Row <> n Then ' only other cells, as same cell cannot be a duplicate
bFound = True ' boolean flag
' found duplicates in cell A{n}
s2 = s2 & vbNewLine & " -> duplicate in A" & n
End If
End If
Next
End If
' notice all found duplicates
If bFound Then
' add value to list of all found duplicate values
' (could be easily split to an array for further analyze)
sFound = sFound & cell & "|"
s = s & cell.Address & " (value=" & cell & ")" & s2 & vbNewLine & vbNewLine
End If
Next
' Messagebox with final result
MsgBox "Duplicate values are " & sFound & vbNewLine & vbNewLine & s, vbInformation, "Found duplicates"
End Sub
Depending on your needs, the example can be modified - for instance, the upper limit of n can be the row value of last cell with data in the range, or the action in case of a True If condition can be edited to extract the duplicate value somewhere else. However, the mechanics of the routine would not change.
