Excel Get different permutation combination of the values - excel

Question

I have an excel with 2 columns,say 10 values each as given in the below diagram. The 10 values in A and B are added in a drop down in column E and column F. I want the column D, "Result", to show me 100 different possible permutations of the values again in a drop down. I tried to write a macro but getting lost somewhere. EDIT: Added the error that i am getting. any help is greatly appreciated. Example of what is expected (remember column E and F are dropdowns)
Below is the macro i have tried:
Sub Combination()
Dim arr1 As Variant
Dim arr2 As Variant
Dim i As Long, j As Long, k As Long
Dim ws As Worksheet
Set ws = ThisWorkbook.Sheets("Sheet1")
arr1 = ws.Range("E1", ws.Range("E" & ws.Rows.Count).End(xlUp).Row).Value
arr2 = ws.Range("F1", ws.Range("F" & ws.Rows.Count).End(xlUp).Row).Value
ws.Range("D1").Value = "Result"
k = 1
For i = LBound(arr1, 1) To UBound(arr1, 1)
For j = LBound(arr2, 1) To UBound(arr2, 1)
ws.Range("D" & k + 1).Value = arr1(i, 1) & ", " & arr2(j, 1)
k = k + 1
If k = 101 Then Exit For
Next j
If k = 101 Then Exit For
Next i
End Sub
Debugger shows an error in this line of code:
arr1 = ws.Range("E1", ws.Range("E" & ws.Rows.Count).End(xlUp).Row).Value
How else am i supposed to read the values in the drop down?

Answer 1

This task doesn't necessarily require a VBA solution: it is achievable using dynamic spreadsheet functions (if you have a relatively recent version of Excel). To my mind, people reach for VBA too readily, when it would be better to exhaust the possibilities of spreadsheet functions first.
1. Calculate the permutations
Put this formula in cell H2:
=LET(a,A2:A11,b,B2:B10,na,ROWS(a),nb,ROWS(b),s,SEQUENCE(na*nb,,0),INDEX(a,1+(INT(s/nb))) & "," & INDEX(b,1+MOD(s,nb)))
2. Set the Data Validation:
Note the # on the end of the $D$2# reference for Source. This tells Excel that the reference is to a dynamic array.
If you don't want the intermediate column displayed, then it can be Hidden or even put on another tab. Currently Excel only allows relatively simple formulae for Data Validation ranges, otherwise this column would not be needed.
Display the selections for Options A & B:
Cell E2 has the formula =LEFT(D2,FIND(",",D2)-1)
Cell F2 has the formula =RIGHT(D2,LEN(D2)-LEN(E2)-1)
You can use MATCH() to recover the index of the option in input list if required, eg =MATCH(E2,A2:A11,0) if that is needed.
Notes:
Using spreadsheet formulae rather than VBA has three benefits:
The sheet can still be saved and shared as a .xlsx file and not
.xlsm, so reducing the number of security warnings;
It is easier to see the results and test;
The sheet will update automatically (if calculation is set to Automatic), whereas a VBA macro would have to be re-run.
EDIT: An alternative, slightly more complicated formula for H2 could be:
=LET(optA,A2,optB,B2,colA,A:A,colB,B:B,
rngA,INDEX(colA,ROW(optA),,1):INDEX(colA,COUNTA(colA),ROW(optA)-1),
rngB,INDEX(colB,ROW(optB),,1):INDEX(colB,COUNTA(colB),ROW(optB)-1),
na,ROWS(rngA),nb,ROWS(rngB),s,SEQUENCE(na*nb,,0),
INDEX(rngA,1+(INT(s/nb))) & "," & INDEX(rngB,1+MOD(s,nb)))
This would handle changes to size of the Option A and Option B columns. An even more adaptive formula could use INDIRECT(), but I am against that on principle!

Answer 2

Answering my own question:
Wrote Macro 1:
Sub Combination1()
Dim arr1 As Variant
Dim arr2 As Variant
Dim i As Long, j As Long, k As Long
Dim ws As Worksheet
Set ws = ThisWorkbook.Sheets("Sheet1")
arr1 = ws.Range("E1", ws.Range("E" & ws.Rows.Count).End(xlUp)).SpecialCells(xlCellTypeConstants).Value
arr2 = ws.Range("F1", ws.Range("F" & ws.Rows.Count).End(xlUp)).SpecialCells(xlCellTypeConstants).Value
ws.Range("D1").Value = "Result"
k = 1
For i = LBound(arr1, 1) To UBound(arr1, 1)
For j = LBound(arr2, 1) To UBound(arr2, 1)
ws.Range("D" & k + 1).Value = arr1(i, 1) & ", " & arr2(j, 1)
k = k + 1
If k = 101 Then Exit For
Next j
If k = 101 Then Exit For
Next i
' Add data validation to column D
With ws.Range("D2", ws.Range("D" & k).End(xlUp))
.Validation.Delete
.Validation.Add Type:=xlValidateList, Formula1:="=" & ws.Range("D2:D" & k).Address
End With
End Sub
This basically reads the values from drop downs.
Macro 2:
Sub Combination2()
Dim arr3 As Variant
Dim ws As Worksheet
Set ws = ThisWorkbook.Sheets("Sheet1")
arr3 = ws.Range("D2", ws.Range("D" & ws.Rows.Count).End(xlUp)).SpecialCells(xlCellTypeConstants).Value
ws.Range("G1").Value = "Result"
For i = LBound(arr3, 1) To UBound(arr3, 1)
ws.Range("G" & i + 1).Value = arr3(i, 1)
Next i
' Add data validation to column G
With ws.Range("G2")
.Validation.Delete
.Validation.Add Type:=xlValidateList, Formula1:="=" & ws.Range("D2:D" & UBound(arr3, 1) + 1).Address
End With
' Clear values in column G except for cell G2
ws.Range("G3", ws.Range("G" & ws.Rows.Count).End(xlUp)).ClearContents
End Sub
This helps to populate the values in another dropdown
Macro 3:
Sub CombinedMacros()
Call Combination1
Call Combination2
End Sub
Happy to "help" people if they have any doubts.