Delete pairs of rows based on value in column

Question

A testing machine tests parts at two different speeds: 50 and 200 rpm. The machine outputs the data for each part at each speed such that

Row 1 = part 1 at 50 rpm
Row 2 = part 1 at 200 rpm
Row 3 = part 2 at 50 rpm
Row 4 = part 2 at 200 rpm

and so on for about 23,000 parts.

If a part number failed for a specific speed, the data would show "niO" in column H of that row, but it would only show it for that speed. I'm trying to write a macro that will check if a row contains the "niO" value, and then delete both that row, and the row for the other speed. Here's the code I have so far:

Sub DeleteFailures()

Dim r As Long

Dim lastrow As Long

lastrow = Cells(Rows.Count, "A").End(xlUp).Row

For r = 1 To lastrow

    If Cells(r, "H").Value = "n.i.O." Then

        If Cells(r, "E").Value = "50" Then

            Rows(r + 1).EntireRow.Delete

            Rows(r).EntireRow.Delete

        ElseIf Cells(r, "E").Value = "200" Then

            Rows(r - 1).EntireRow.Delete

            Rows(r).EntireRow.Delete

        End If

    Else

    End If

Next

End Sub

This doesn't seem to want to work for me. I think the problem might be that it skips a row every time one is deleted, but I'm not sure. Is there another approach that might work better?

Answer 1

It's exactly the reason you're thinking about. To make it work you should loop beginning the bottom:

For r = lastrow To 1 Step -1

The whole For loop block I believe should look like this (changed ElseIf part):

For r = lastrow To 1 Step -1
    If Cells(r, "H").Value = "n.i.O." Then
        If Cells(r, "E").Value = "50" Then
            Rows(r + 1).EntireRow.Delete
            Rows(r).EntireRow.Delete
        ElseIf Cells(r, "E").Value = "200" Then
            Rows(r).EntireRow.Delete
            Rows(r - 1).EntireRow.Delete
            r = r - 1
        End If
    Else
    End If
Next