Hide or delete rows with non-duplicate, unique values in first column

Check Excel Data>Filter>Advance Filter.....check unique values only
Infuse

That filter hides duplicate rows. None of my rows are exact duplicates. It also keeps one row of a set of duplicates.

The following assumes the matching Content_IDs are in consecutive rows, if not then at least this is a start.

Click the first Content_ID cell then:

Insert > Name > Define and in the 'Names in workbook:' box enter 'ID_Start', then click OK.

Right click on the sheet name, View Code and paste the following:

Public Sub DeleteDupeIDs()
'Replace Worksheets(1) as appropriate
Dim ID_StartRow, ID_EndRow, ID_Col, y As Integer
Dim R1, R2 As Range
ID_Col = Range("ID_Start").Column

ID_StartRow = Worksheets(1).Range("ID_Start").Row
ID_EndRow = Worksheets(1).Range(Cells(65535, ID_Col), Cells(65535, ID_Col)).End(xlUp).Row

Set R1 = Worksheets(1).Range(Cells(65535, 1), Cells(65535, 1))
For y = ID_StartRow To ID_EndRow
If Cells(y, ID_Col).Value = Cells(y - 1, ID_Col).Value Then
Set R2 = Worksheets(1).Range(Cells(y, 1), Cells(y, 1))
Set R1 = Union(R1, R2)
End If
Next y
'R1.Select
R1.EntireRow.Hidden = True
'R1.Delete
'Application.Goto Sheets(1).Cells(1, 1), True
End Sub

To Run, click Tools > Macro, Macros then DeleteDupeIDs and Run.

Regards
Anthony

Whoops, just re-read your post, you want to hide/delete the unique rows not the duplicate rows. I'm not too hot with VBA, I could do this in C#. I'll give it some more thought.

I've done something similar to this in C#.

The quick way to do this in C# would be to use a Dictionary or HashTable a quick search on google revealed this:

HASH TABLES
============
The best way to create hash tables in Excel VBA is to set a reference
to the Microsoft Scripting Runtime library. It contains a Dictionary
object that works like a Perl hash structure.

Thanks, but I am not a programmer. I was hoping for a solution using a formula or macro.

I have a formula, for example, that uses conditional formatting to toggle highlighting of rows each time the content ID changes. I was hoping for a similar solution to hide or delete the rows with a unique content ID.