Which the fastest way to sum two range? - excel

Question

I need summ column values from multiple workbooks and worksheets in single worksheet. If i'm trying do it like this:
While targetCell.Row <> LastRow
targetCell.Value = targetCell.Value + sourseCell.Value
Set sourseCell = sourseSheet.Cells(sourseCell.Row + 1, sourseCell.Column)
Set targetCell = targetSheet.Cells(targetCell.Row + 1, targetCell.Column)
Wend
It takes too much time(Hours!!!).
Like this:
targetSheet.Range("D14:BJ" & LastRow).Value = targetSheet.Range("D14:BJ" & LastRow).Value + sourseSheet.Range("D14:BJ" & LastRow).Value
I'm sometimes have error type mismatch
Full code:
For Each foldername In subFolders
If foldername <> ThisWorkbook.path Then
filePath = foldername & fileName
Dim app As New Excel.Application
app.Visible = False
Dim book As Excel.Workbook
Set book = app.Workbooks.Add(filePath)
For Each targetSheet In ActiveWorkbook.Worksheets
Dim sourseSheet As Worksheet
Set sourseSheet = book.Worksheets(targetSheet.Name)
Call CopyColumn(targetSheet, sourseSheet, LastRow)
Next
book.Close SaveChanges:=False
app.Quit
Set app = Nothing
End If
Next
Sub CopyColumn(targetSheet, sourseSheet As Worksheet, LastRow As Integer)
Dim sourseCell, targetCell As Range
Set targetCell = targetSheet.Cells(14,"D")
Set sourseCell = sourseCell.Cells(14,"CH")
While targetCell.Row <> LastRow
targetCell.Value = targetCell.Value + sourseCell.Value
Set sourseCell = sourseSheet.Cells(sourseCell.Row + 1, sourseCell.Column)
Set targetCell = targetSheet.Cells(targetCell.Row + 1, targetCell.Column)
Wend
End Sub

Answer 1

Copying the ranges to Variant arrays is quite fast. Your subroutine amended and commented below:
Sub CopyColumn(targetSheet As Worksheet, sourseSheet As Worksheet, LastRow As Long)
' LastRow as Integer will give an error for rows > 32,767, use Long instead
' Check the syntax: sourseCell, targetCell as Range means:
' sourceCell as Variant, targetCell as Range. We should include
' "as Range" after each variable declaration if we want it to be a Range
Dim sourseCell As Range, targetCell As Range
Dim lCount As Long
Dim vTarget, vSource
' I kept the names targetCell, sourseSheet, but turned them to ranges
' You might want to change sourseSheet to sourceSheet
With targetSheet
Set targetCell = .Range(.Cells(14, "D"), .Cells(LastRow, "D"))
End With
' I assume you mean sourceSheet instead of sourceCell,
' in your original code?
With sourseSheet
Set sourseCell = .Range(.Cells(14, "CH"), .Cells(LastRow, "CH"))
End With
vTarget = targetCell.Value2
vSource = sourseCell.Value2
' If there is a change you do not have numeric values
' this needs error trapping
For lCount = LBound(vTarget, 1) To UBound(vTarget, 1)
vTarget(lCount, 1) = vTarget(lCount, 1) + vSource(lCount, 1)
Next lCount
targetCell.Value = vTarget
End Sub
Testing:
Option Explicit
Private Declare Function GetTickCount Lib "kernel32.dll" () As Long
Sub test_copy_column()
Dim targetSheet As Worksheet, sourseSheet As Worksheet, LastRow As Long, _
tick As Long
' Maybe change sourseSheet to sourceSheet :)
tick = GetTickCount ' Clock count
Set targetSheet = Sheet1
Set sourseSheet = Sheet1
LastRow = 50000 ' I inputted random numbers for testing
CopyColumn targetSheet, sourseSheet, LastRow
MsgBox "Time to copy: " & GetTickCount - tick & " milliseconds"
End Sub
Result:
Relevant SO question here
I hope that helps!

Answer 2

for fast non-VBA solution, open all workbooks and insert following formula into a helper sheet:
=first_cell_from_source_workbook + first_cell_from_target_workbook + ...
copy the formula to cover whole range you need to cover.
copy & paste-special-as-values to target range if you wish to replace the original values in target range..
each time you wish to recalculate, make sure all source workbooks are open.