VBA: How do I get unique values in a column and insert it into an array? - vba

Question

I have seen multiple codes regarding this topic but I can't seem to understand it.
For instance, if I have a column that records people names, I want to record all unique names into the array.
So if I have a column of names
David
Johnathan
Peter
Peter
Peter
Louis
David
I want to utilize VBA to extract unique names out of the column and place it into an array so when I call the array it would return these results
Array[0] = David
Array[1] = Johnathan
Array[2] = Peter
Array[3] = Louis

Answer 1

Despite a Collection being mentioned and being a possible solution, it is far more efficient to use a Dictionary as it has an Exists method. Then it's just a matter of adding the names to the dictionary if they don't already exist, and then extracting the keys to an array when you're done.
Note that I've made the name comparisons case-sensitive, but you can change that if necessary, to case-insensitive.
Option Explicit
Sub test()
'Extract all of the names into an array
Dim values As Variant
values = Sheet1.Range("Names").Value2 'Value2 is faster than Value
'Add a reference to Microsoft Scripting Runtime
Dim dic As Scripting.Dictionary
Set dic = New Scripting.Dictionary
'Set the comparison mode to case-sensitive
dic.CompareMode = BinaryCompare
Dim valCounter As Long
For valCounter = LBound(values) To UBound(values)
'Check if the name is already in the dictionary
If Not dic.Exists(values(valCounter, 1)) Then
'Add the new name as a key, along with a dummy value of 0
dic.Add values(valCounter, 1), 0
End If
Next valCounter
'Extract the dictionary's keys as a 1D array
Dim result As Variant
result = dic.Keys
End Sub

Answer 2

use Dictionary object and build a Function that returns your array
Function GetUniqeNames(myRng As Range) As Variant
Dim cell As Range
With CreateObject("Scripting.Dictionary") ' instantiate and reference a Dictionary object
For Each cell In myRng ' loop through passed range
.Item(cell.Value2) = 1 ' store current cell name into referenced dictionary keys (duplicates will be overwritten)
Next
GetUniqeNames = .keys ' write referenced dictionary keys into an array
End With
End Function
that you can exploit in your main code as follows
Sub main()
Dim myArray As Variant
With Worksheets("mysheet") ' change "mysheet" to your actual sheet name
myArray = GetUniqeNames(.Range("A1", .Cells(.Rows.Count, 1).End(xlUp))) ' this will take the referenced sheet column A range from row 1 down to last not empty one
End With
End Sub

Answer 3

Is this a VBA question or a question about programming logic? Use a loop on the column with the data. Check each name against the list of existing data items. If it exists in the list, move on the the next name. If it does not exist in the list, add it.
The "list" is a concept, not a concrete tool. It can be a VBA dictionary, if you are comfortable using that. Or it can be a VBA array, which may not perform as fast as a dictionary, but may be more familiar.
Then again, if you add the data to the Excel Data Model, you can use the Distinct aggregation of a pivot table to list out the unique values.
Without more background it's hard to tell if VBA or Data Model is your best approach. Many VBA solutions get created because people are not aware of Excel's capabilities.

Answer 4

You could use Excel functionality like that.
Sub UniqueNames()
Dim vDat As Variant
Dim rg As Range
Dim i As Long
Set rg = Range("A1:A7")
rg.RemoveDuplicates Columns:=Array(1), Header:=xlNo
With ActiveSheet
vDat = WorksheetFunction.Transpose(.Range("A1:" & .Range("A1").End(xlDown).Address))
End With
For i = LBound(vDat) To UBound(vDat)
Debug.Print vDat(i)
Next i
End Sub
Code is based on your example data, i.e. I put your data into column 1. But the code will also alter the table. If you do not want that you have to use other solutions or put the data beforehand in a temporary sheet.

Answer 5

If you dont want to use "Scripting.Dictionary" and your excel does not have Worksheet.unique(...) like mine
Public Function IsInArray(stringToBeFound As String, arr As Variant) As Boolean
If UBound(arr) >= 0 Then
IsInArray = Not IsError(Application.Match(stringToBeFound, arr, 0))
Else
IsInArray = False
End If
End Function
Public Function GetUniqueValuesFromColumn(ws As Worksheet, sourceColNum As Long, Optional firstRow As Long = 2) As Variant
Dim val As String
Dim i As Long
Dim arr() As Variant
arr = Array()
For i = firstRow To ws.Cells(Rows.Count, sourceColNum).End(xlUp).Row
val = ws.Cells(i, sourceColNum)
If Not IsInArray(val, arr) Then
ReDim Preserve arr(UBound(arr) + 1)
arr(UBound(arr)) = val
End If
Next i
GetUniqueValuesFromColumn = arr
End Function
Then call it like GetUniqueValuesFromColumn(ThisWorkbook.Worksheets("SomeList"), 1)