Hiding multiple rows based on cell values - vba

Question

I have an algorithm that works fine to hide all rows where, in a specified named range, a given row has the value 0. It's straightforward enough:
Public Sub MasquerLignesAZeroRapport(rap As Worksheet)
Dim cell As Range
rap.Rows.Hidden = False
For Each cell In rap.Range("Ra_LignesAZero")
If Round(cell.Value, 0) = 0 Then
cell.EntireRow.Hidden = True
End If
Next cell
End Sub
This, however, takes a bit of time even when calculation and screen updating are turned off and I have tried different other methods without success (using a filter and hiding all visible rows but removing the filter unhides the rows, the same goes for setting the row height to 0).
Is there a faster alternative ? I can live with that slow algorithm but it would be a welcome improvement as this macro may be run against 1-6 reports in a single run.

Answer 1

Here are a few optimizations:
Public Sub MasquerLignesAZeroRapport(rap As Worksheet)
'Optimization #1: as you pointed out, turning off calculations
' and screen updating makes a difference.
Application.Calculation = xlCalculationManual
Application.ScreenUpdating = False
rap.Rows.Hidden = False
'Optimization #2: instead of loading each cell as a range,
' with all the associated properties, load JUST the values
' into a 2 dimensional array.
Dim values() As Variant
values = rap.Range("Ra_LignesAZero")
For r = 1 To UBound(values, 1)
For c = 1 To UBound(values, 2)
If Round(values(r,c), 0) = 0 Then
rap.Rows(r).Hidden = True
'Optimization #3: if we have already determined
' that the row should be hidden, no need to keep
' looking at cells in the row - might as well break out of the For:
Exit For
End If
Next
Next
Application.ScreenUpdating = True
Application.Calculation = xlCalculationAutomatic
End Sub