Make a new column without duplicates VBA?

Question

I have a column of cells whose values are something like this:

a
a
b
b
c
c
c
c
d
e
f
f

etc.

I\'m looking to take the non-duplicate

Answer 1

I use a collection, which can't have duplicate keys, to get the unique items from a list. Try to add each item to a collection and ignore the errors when there's a duplicate key. Then you'll have a collection with a subset of unique values

Sub MakeUnique()

    Dim vaData As Variant
    Dim colUnique As Collection
    Dim aOutput() As Variant
    Dim i As Long

    'Put the data in an array
    vaData = Sheet1.Range("A1:A12").Value

    'Create a new collection
    Set colUnique = New Collection

    'Loop through the data
    For i = LBound(vaData, 1) To UBound(vaData, 1)
        'Collections can't have duplicate keys, so try to
        'add each item to the collection ignoring errors.
        'Only unique items will be added
        On Error Resume Next
            colUnique.Add vaData(i, 1), CStr(vaData(i, 1))
        On Error GoTo 0
    Next i

    'size an array to write out to the sheet
    ReDim aOutput(1 To colUnique.Count, 1 To 1)

    'Loop through the collection and fill the output array
    For i = 1 To colUnique.Count
        aOutput(i, 1) = colUnique.Item(i)
    Next i

    'Write the unique values to column B
    Sheet1.Range("B1").Resize(UBound(aOutput, 1), UBound(aOutput, 2)).Value = aOutput

End Sub