Most efficient way to delete row with VBA

问题:

I currently have a macro that I use to delete a record if the ID doesn't exist in a list of ID's I created from an XML document. It does work like I want it to, however I have over 1000 columns in the spreadsheet (one for each day of the year until end of 2015) so it takes ages to delete the row and it can only do 1 or 2 before it says "Excel ran out of resources and had to stop". Below is the code I'm using for the macro, is there another way I can do this so that Excel doesn't run of of resources?

Sub deleteTasks()

Application.ScreenUpdating = False

Dim search As String
Dim sheet As Worksheet
Dim cell As Range, col As Range
Set sheet = Worksheets("misc")
Set col = sheet.Columns(4)

ActiveWorkbook.Sheets("Schedule").Activate
ActiveSheet.Range("A4").Select
ActiveSheet.Unprotect
ActiveSheet.Range("A:C").EntireColumn.Hidden = False

Do While ActiveCell.Value <> ""

    search = ActiveCell.Value

    Set cell = col.Find(What:=search, LookIn:=xlValues, _
                 LookAt:=xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
                 MatchCase:=False, SearchFormat:=False)

    If cell Is Nothing Then 'If the taskID is not in the XML list

    Debug.Print "Deleted Task: " & ActiveCell.Value
    Selection.EntireRow.Delete

    End If

    ActiveCell.Offset(1, 0).Select 'Select next task ID

Loop

ActiveSheet.Range("A:B").EntireColumn.Hidden = True
ActiveSheet.Protect
End Sub

After trying lots of different options, including all the answers listed below. I have realized that whatever the method is, deleting a row with ~1100 columns is going to take a while on my average laptop (2.20 Ghz, 4GB RAM). Since the majority of the rows are empty I have found alternative method which is a lot faster. I just clear the cells which contain data (A:S) and then resize the table to remove the row where I just deleted the data from. This end result is exactly the same as entireColumn.Delete. Below is the code I'm using now

'New method - takes about 10 seconds on my laptop
Set ws = Worksheets("Schedule")
Set table = ws.ListObjects(1)
Set r = ws.Range("A280:S280")

r.Clear

table.Resize Range("A3:VZ279")

Using anything involving EntireColumn.Delete or just manually selecting the row and deleting it takes about 20-30 seconds on my laptop. Of course this method only works if your data is in a table.

回答1:

The short answer:

Use something like

ActiveSheet.Range(DelStr).Delete
' where DelStr = "15:15" if you want to delete row 15
'              = "15:15,20:20,32:32" if you want to delete rows 15,20 and 32

The long answer:

Important: If you have ~ 30 / 35 rows to delete, the following code works very efficiently. Beyond which it would throw up an error. For code to handle arbitrary number of rows efficiently see the very long answer below this.

If you have a function which lets you list out which rows you want to delete, try the code below. This is what I use to very efficiently delete multiple rows with minimum overhead. (the example assumes that you've obtained the rows you need to delete through some program, here I manually feed them in):

Sub DeleteRows()
    Dim DelRows() As Variant
    ReDim DelRows(1 To 3)

    DelRows(1) = 15
    DelRows(2) = 18
    DelRows(3) = 21

    '--- How to delete them all together?

    Dim i As Long
    For i = LBound(DelRows) To UBound(DelRows)
        DelRows(i) = DelRows(i) & ":" & DelRows(i)
    Next i

    Dim DelStr As String
    DelStr = Join(DelRows, ",")

    ' DelStr = "15:15,18:18,21:21"
    '           
    '    IMPORTANT: Range strings have a 255 character limit
    '    See the other code to handle very long strings

    ActiveSheet.Range(DelStr).Delete
End Sub

The (very long) efficient solution for arbitrary number of rows and benchmark results:

Here are the benchmark results obtained by deleting rows (Time in seconds vs. no. of rows).

The rows are on a clean sheet and contain a volatile formula in the D column from D1:D100000

i.e. for 100,000 rows, they have a formula =SIN(RAND())

The code is long and not too pretty, but it splits the DelStr into 250 character substrings and forms a range using these. Then the new DeleteRng range is deleted in a single operation.

The time to delete may depend on the contents of the cells. The testing/benchmarking, in congruence with a bit of intuition suggests the following results.

• Sparse rows/empty cells delete fastest
• Cells with values take somewhat longer
• Cells with formulas take even longer
• Cells which feed into formulas in other cells take longest as their deletion triggers the #Ref reference error.

Code:

Sub DeleteRows()

    ' Usual optimization
    ' Events not disabled as sometimes you'll need to interrupt
    ' You can optionally keep them disabled

    Application.Calculation = xlCalculationManual
    Application.ScreenUpdating = False

    ' Declarations...

    Dim DelRows() As Variant

    Dim DelStr As String, LenStr As Long
    Dim CutHere_Str As String
    Dim i As Long

    Dim MaxRowsTest As Long
    MaxRowsTest = 1000

    ' Here I'm taking all even rows from 1 to MaxRowsTest
    ' as rows to be deleted

    ReDim DelRows(1 To MaxRowsTest)

    For i = 1 To MaxRowsTest
        DelRows(i) = i * 2
    Next i

    '--- How to delete them all together?

    LenStr = 0
    DelStr = ""

    For i = LBound(DelRows) To UBound(DelRows)
        LenStr = LenStr + Len(DelRows(i)) * 2 + 2

        ' One for a comma, one for the colon and the rest for the row number
        ' The goal is to create a string like
        ' DelStr = "15:15,18:18,21:21"

        If LenStr > 200 Then
            LenStr = 0
            CutHere_Str = "!"       ' Demarcator for long strings
        Else
            CutHere_Str = ""
        End If

        DelRows(i) = DelRows(i) & ":" & DelRows(i) & CutHere_Str
    Next i

    DelStr = Join(DelRows, ",")

    Dim DelStr_Cut() As String
    DelStr_Cut = Split(DelStr, "!,")
    ' Each DelStr_Cut(#) string has a usable string

    Dim DeleteRng As Range
    Set DeleteRng = ActiveSheet.Range(DelStr_Cut(0))

    For i = LBound(DelStr_Cut) + 1 To UBound(DelStr_Cut)
        Set DeleteRng = Union(DeleteRng, ActiveSheet.Range(DelStr_Cut(i)))
    Next i

    DeleteRng.Delete

    Application.Calculation = xlCalculationAutomatic
    Application.ScreenUpdating = True

End Sub

The code to generate the formulas in a blank sheet is

Sub FillRandom()
    ActiveSheet.Range("D1").FormulaR1C1 = "=SIN(RAND())"
    Range("D1").AutoFill Destination:=Range("D1:D100000"), Type:=xlFillDefault
End Sub

And the code to generate the benchmark results above is

Sub TestTimeForDeletion()

        Call FillRandom

        Dim Time1 As Single, Time2 As Single
        Time1 = Timer

        Call DeleteRows

        Time2 = Timer
        MsgBox (Time2 - Time1)
End Sub

Note: Many thanks to brettdj for pointing out the error which gets thrown when the length of DelStr exceeding 255 characters. It seems to be a known problem and as I painfully found out, it still exists for Excel 2013.

回答2:

This code uses AutoFilter and is significantly faster than looping through rows.

I use it daily and it should be pretty easy to figure out.

Just pass it what you're looking for and the column to search in.

You could also hard-code the column if you want.

private sub PurgeRandy
    Call FindDelete("F", "Randy")
end sub

Public Sub FindDelete(sCOL As String, vSearch As Variant) 'Simple find and Delete
Dim lLastRow As Integer
Dim rng As Range
Dim rngDelete As Range
    Range(sCOL & 1).Select
    [2:2].Insert
    [2:2] = "***"
    Range(sCOL & ":" & sCOL).Select

    With ActiveSheet
        .UsedRange
            lLastRow = .Cells.SpecialCells(xlCellTypeLastCell).Row
        Set rng = Range(sCOL & 2, Cells(lLastRow, sCOL))
            rng.AutoFilter Field:=1, Criteria1:=vSearch
        Set rngDelete = rng.SpecialCells(xlCellTypeVisible)
            rng.AutoFilter
            rngDelete.EntireRow.Delete
        .UsedRange
    End With
End Sub

回答3:

In this case a simple working formula can be used to see if each of the values in your range to be tested (column A of schedule) exist in column F of misc

In B4 it would =MATCH(A4,misc!D:D,0)

This can be used manually or with code for an efficient delete as the formula by design returns an error if there is no match which we can efficiently delete with VBA with either:

• AutoFilter
• SpecialCells (the design piece*)

In xl2007 note that there is a limit of 8192 discrete areas that can be selected with SpecialCells

code

Sub ReCut()
Dim ws1 As Worksheet
Dim ws2 As Worksheet
Dim rng1 As Range

Set ws1 = Sheets("misc")
Set ws2 = Sheets("schedule")

With Application
.ScreenUpdating = False
.EnableEvents = False
.DisplayAlerts = False
End With

Set rng1 = ws2.Range(ws2.[a4], ws2.Cells(Rows.Count, "A").End(xlUp))
ws2.Columns(2).Insert
With rng1.Offset(0, 1)
     .FormulaR1C1 = "=MATCH(RC[-1],'" & ws1.Name & "'!C[2],0)"
     On Error Resume Next
    .Cells.SpecialCells(xlCellTypeFormulas, xlErrors).EntireRow.Delete
     On Error GoTo 0
End With

ws2.Columns(2).Delete

With Application
.ScreenUpdating = True
.EnableEvents = True
.DisplayAlerts = True
End With
End Sub

回答4:

Note: I don't have enough "reputation" to add my comments thus posting as answer. Credit to hnk for wonderful answer (Long Answer). I have one edit as suggestion:

Once you split the long string and in case the last block is more than the set character then it is having "!" at the end which is throwing error for range method. Addition of IF statement and MID is ensuring that there is no such character.

To handle that, use:

For i = LBound(DelStr_Cut) + 1 To UBound(DelStr_Cut)
    If Right(DelStr_Cut(i), 1) = "!" Then
        DelStr_Cut(i) = Mid(DelStr_Cut(i), 1, Len(DelStr_Cut(i)) - 1)
        Set DeleteRng = Union(DeleteRng, ActiveSheet.Range(DelStr_Cut(i)))
    Else
        Set DeleteRng = Union(DeleteRng, ActiveSheet.Range(DelStr_Cut(i)))
    End If
Next i

Thanks, Bakul