Delete rows (dynamic amount) based on cell's content - vba

Question

Sorry if this is simple, this is my first time trying VBA.
So I want this macro to get rid of rows I don't need, and for every entity it has a total field (about every 20 records or so) and I made this script:
Dim i As Integer
Dim LastRow As Integer
LastRow = Range("A65536").End(xlUp).Row
For i = 3 To LastRow
If Range("C" & i) = "Result" Then
Rows(i & ":" & i).Select
Selection.Delete Shift:=x1Up
End If
Next
And that worked perfectly! Then I tried to a similar thing.. I tried to go through each row (record) in a data set and then if a certain field does not contain the string "INVOICE" then I don't need that row and I can delete it. So I just added into my current loop (why loop twice?) So now it looks like this:
Dim i As Integer
Dim LastRow As Integer
LastRow = Range("A65536").End(xlUp).Row
For i = 3 To LastRow
If Range("C" & i) = "Result" Then
Rows(i & ":" & i).Select
Selection.Delete Shift:=x1Up
End If
If Not InStr(1, Range("Q" & i), "INVOICE") Then
Rows(i & ":" & i).Select
Selection.Delete Shift:=x1Up
End If
Next
That second bit as far as I can tell just randomly starts deleting rows with no rhyme or reason. Rows where the Q field doesn't contain invoice sometimes stay sometimes go, and same if it does contain invoice. Any idea what I'm doing wrong?

Answer 1

You should OR your conditions together so that if either reason exists the line is deleted. Otherwise since you're deleting lines within a preset range, you'll end up skipping more lines than you are currently. Currently it looks like you skip a line everytime you delete one, so you're missing any consecutive cases. Tim's advice to work from the last row up is spot on.
For i = LastRow to 3 Step -1
If Range("C" & i) = "Result" OR Not InStr(1, Range("Q" & i), "INVOICE") Then
Rows(i & ":" i).Delete Shift:=x1Up
End If
Next i

Answer 2

There are indeed two approaches: AutoFilter and For Loop. Of the two, AutoFilter is much faster especially with large datasets, but it will often need a very good set-up. The For Loop is easy, but it has marginal returns, especially when your data start hitting 100k rows or more.
Also, Not InStr(1, Range("Q" & i), "INVOICE") might seem like the best way but IMHO it's not. InStr returns a number, so it's better if you either do further comparison like Not InStr(1, Range("Q" & i), "INVOICE") > 0 or just simply InStr(1, Range("Q" & i), "INVOICE") = 0. In any case, I used the former in my second code below.
Following are both approaches. They are tested on simple data. The code might seem a bit bulky, but the logic is sound. Refer to the comments as well for other things.
AutoFilter approach:
Sub RemoveViaFilter()
Dim WS As Worksheet: Set WS = ThisWorkbook.Sheets("ModifyMe")
Dim LastRow As Long
Application.ScreenUpdating = False
With WS
'--For condition "Result"
.AutoFilterMode = False
LastRow = .Cells(Rows.Count, 1).End(xlUp).row '--Compatible if there are more rows.
With Range("A2:Q" & LastRow) '--Assuming your header is in Row 2 and records start at Row 3.
.AutoFilter Field:=3, Criteria1:="Result" '--Field:=3 is Column C if data starts at A
.Cells.Offset(1, 0).SpecialCells(xlCellTypeVisible).EntireRow.Delete '--Delete the visible ones.
End With
'--For condition "<>*INVOICE*"
.AutoFilterMode = False
LastRow = .Cells(Rows.Count, 1).End(xlUp).row
With Range("A2:Q" & LastRow)
.AutoFilter Field:=17, Criteria1:="<>*INVOICE*" '--Field:=17 is Column Q if data starts at A
.Cells.Offset(1, 0).SpecialCells(xlCellTypeVisible).EntireRow.Delete
End With
.AutoFilterMode = False
End With
Application.ScreenUpdating = True
End Sub
For-loop approach:
Sub RemoveViaLoop()
Dim WS As Worksheet: Set WS = ThisWorkbook.Sheets("Sheet6")
Dim LastRow As Long: LastRow = WS.Cells(Rows.Count, 1).End(xlUp).row
Dim Iter As Long
Application.ScreenUpdating = False
With WS
For Iter = LastRow To 3 Step -1 '--Move through the rows from bottom to up by 1 step (row) at a time.
If .Range("C" & Iter) = "Result" Or Not InStr(1, .Range("Q" & Iter).Value, "Invoice") > 0 Then
.Rows(Iter).EntireRow.Delete
End If
Next Iter
End With
Application.ScreenUpdating = True
End Sub
Let us know if this helps.