Convert Excel Array formula into VBA code - excel

Question

I have two set of range named as LIST_KEY and LIST_CAT. In Column A, user will add some data which will contain one of the one of the text from LIST_KEY. I would like to get corresponding Category list from LIST_CAT depends upon the Key value
I am using below VBA code to achieve this. This include a Array formula.
Sub match()
Dim ss As Workbook
Dim test As Worksheet
Set ss = Excel.Workbooks("test.xlsm")
Set test = ss.Worksheets("Sheet1")
For i = 2 To test.Cells(Rows.Count, "A").End(xlUp).Row
Cells(i, "B").FormulaArray = "=INDEX(LIST_CAT,MATCH(TRUE,ISNUMBER(SEARCH(LIST_KEY,RC[-1])),0))"
Cells(i, "B").Formula = Cells(i, "B").Value
Next i
End Sub
This code works perfect if there is less data to fetch. But in my original use case, I will have around 8000 rows. Due to this large number of columns excel will go to not responding state after 2-3 minutes.
Instead of adding Array formula to column B, Is there anyway to convert that into VBA to run this faster. Sorry, I am new to this VBA stuff and dont have much experience

Answer 1

Try the following code, which uses arrays instead of worksheet formulas...
Option Explicit
Sub GetCategories()
Dim sourceWorkbook As Workbook
Set sourceWorkbook = Workbooks("test.xlsm")
Dim sourceWorksheet As Worksheet
Set sourceWorksheet = sourceWorkbook.Worksheets("Sheet1")
Dim lookupArray As Variant
lookupArray = sourceWorkbook.Names("LIST_KEY").RefersToRange.Value
Dim returnArray As Variant
returnArray = sourceWorkbook.Names("LIST_CAT").RefersToRange.Value
Dim tableArray As Variant
Dim lastRow As Long
With sourceWorksheet
lastRow = .Cells(.Rows.Count, "a").End(xlUp).Row
tableArray = .Range("A2:B" & lastRow).Value
End With
Dim desc As String
Dim i As Long
Dim j As Long
For i = LBound(tableArray, 1) To UBound(tableArray, 1)
desc = tableArray(i, 1)
For j = LBound(lookupArray, 1) To UBound(lookupArray, 1)
If InStr(1, desc, lookupArray(j, 1), vbTextCompare) > 0 Then
tableArray(i, 2) = returnArray(j, 1)
Exit For
End If
Next j
Next i
sourceWorksheet.Range("B2").Resize(UBound(tableArray, 1), 1).Value = Application.Index(tableArray, 0, 2)
End Sub