VBA that copies rows into new sheet based on each row's cell contents (example included) - vba

Question

So I'm hoping for some help to automate a process that will otherwise involve copying and editing some 10,000 rows.
This is stuff relating to location data. Essentially, there are tons of these Master Rows but they do not have individual rows for Unit Numbers. I am hoping to get something to expand these into individual Unit Number rows based on what is in Column N. Column N is intended to follow a strict format of being a comma-seperated single cell list for each row.
Below is an example from Sheet 1 of what each row will have and needs to be expanded upon. Note that Column N is green and follows a consistent formatting and this will be the determinant for how many times these rows will each be expanded upon.
Below is Sheet 2 and what I want the VBA to create from Sheet 1. You can see that each row has been expanded based on the contents of Column N from Sheet 1.
Like I said, it is expected that this will involve some several thousand rows to create.

Answer 1

Option Explicit
Sub Tester()
Dim sht1, sht2, rwSrc As Range, rwDest As Range, v, arr, n
Set sht1 = ThisWorkbook.Sheets("Sheet1")
Set sht2 = ThisWorkbook.Sheets("Sheet2")
sht2.Range("A2:M2").Resize(3, 13).Value = sht1.Range("A2:M2").Value
Set rwDest = sht2.Range("A2:M2") 'destination start row
Set rwSrc = sht1.Range("A2:M2") 'source row
Do While Application.CountA(rwSrc) > 0
v = rwSrc.EntireRow.Cells(1, "N").Value 'list of values
If InStr(v, ",") > 0 Then
'list of values: split and count
arr = Split(v, ",")
n = UBound(arr) + 1
Else
'one or no value
arr = Array(v)
n = 1
End If
'duplicate source row as required
rwDest.Resize(n, 13).Value = rwSrc.Value
'copy over the unit values
rwDest.Cells(1, "G").Resize(n, 1).Value = Application.Transpose(arr)
'offset to next destination row
Set rwDest = rwDest.Offset(n, 0)
'next source row
Set rwSrc = rwSrc.Offset(1, 0)
Loop
End Sub

Answer 2

This does the work in same sheet... Pls copy the value to "Sheet2" before executing this. Not sure about efficiency though.
Public Sub Test()
Dim lr As Long ' To store the last row of the data range
Dim counter As Long
Dim Str As String ' To store the string in column N
lr = Range("N65536").End(xlUp).Row 'Getting the last row of the data
For i = lr To 2 Step -1
Str = Range("N" & i).Value ' Getting the value from Column N
counter = 1
For Each s In Split(Str, ",")
If counter > 1 Then
Range("A" & (i + counter - 1)).EntireRow.Insert ' Inserting rows for each value in column N
Range("G" & (i + counter - 1)).Formula = s ' Updating the value in Column G
Else
Range("G" & i).Formula = s ' No need to insert a new row for first value
End If
counter = counter + 1
Next s
Next i
lr = Range("G65536").End(xlUp).Row
' Pulling down other values from the first value row other rows
Range("A1:N" & lr).Select
Selection.SpecialCells(xlCellTypeBlanks).Select
Selection.FormulaR1C1 = "=R[-1]C"
' Pasting the data as Values to avoid future formula issues.
Range("A1:N" & lr).Copy
Range("A1:N" & lr).PasteSpecial xlPasteValues
MsgBox "Done"
End Sub