duplicates in a lsit

[Dr. Inferno]

I haven't gotten an answer for this one yet. The user can enter a number of items in a list. How can I determine what item has been repeated the most? In the list
1
2
3
there would be none. However, in the list
1
1
2
3
it would be 1. And in the list
1
1
2
2
3
it would be 1, 2. How could I do that?

[Aaron Young]

Try this, it works fastest with a Sorted List, but is still quick either way..
private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (byval hwnd as Long, byval wMsg as Long, byval wParam as Long, lParam as Any) as Long
private Const LB_FINDSTRINGEXACT = &H1A2

private Sub Command1_Click()
Dim iIndex as Long
Dim iMatch as Long
Dim iCopies as Long
Dim iHighest as Long
Dim aCommon() as Long
Dim sString as string
Dim bSkip as Boolean

for iIndex = 0 to List1.ListCount - 1
iCopies = 0
iMatch = -1
bSkip = false
'Skip this one if it's the same as the last Item Checked
If iIndex then bSkip = (List1.List(iIndex) = List1.List(iIndex - 1))
'Skip this one if there's a previous instance of it in the List
If Not bSkip then bSkip = (SendMessage(List1.hwnd, LB_FINDSTRINGEXACT, -1, byval List1.List(iIndex)) < iIndex)
'While there are other Instances in the List..
While iMatch <> iIndex And Not bSkip
'Increment the No of Copies Found of this Item
iCopies = iCopies + 1
'Find the next Copy..
iMatch = SendMessage(List1.hwnd, LB_FINDSTRINGEXACT, IIf(iMatch < 0, iIndex, iMatch), byval List1.List(iIndex))
Wend
'If there were more than 1 Copies
If iCopies > 1 And Not bSkip then
'If the No. of Copies is Greater or the Same as the Highest so far..
If iCopies >= iHighest then
If iCopies > iHighest then
'new Highest Copies
ReDim aCommon(0)
else
'Another Item with the same highest amount of Copies
ReDim Preserve aCommon(UBound(aCommon) + 1)
End If
'Store this Index
aCommon(UBound(aCommon)) = iIndex
'Remember the Highest No. of Copies
iHighest = iCopies
End If
End If
next
If iHighest then
'If Copies were Found..
for iIndex = 0 to UBound(aCommon)
sString = sString & ", " & List1.List(aCommon(iIndex))
next
MsgBox "Most Repeated Item(s): " & vbCrLf & mid$(sString, 3) & _
vbCrLf & vbCrLf & "Repeated " & iHighest & " Times.", _
vbInformation + vbOKOnly, "Repeats"
else
'No Copies Found..
MsgBox "No Items were Repeated", vbInformation + vbOKOnly, "No Repeats"
End If
End Sub



Aaron Young
Analyst Programmer
ajyoung@pressenter.com
aarony@redwingsoftware.com