Optimising a For Each loop used for counting Excel VBA - excel

Question

I'm currently working on a Quality Concern log that will be used at my place of work to track the quality concerns, and output specific data to the management via a dashboard.
One of the calculations i have, go through rows in a log and counts the number of rows that meet a certain criteria. It is essentially a CountIf function, but with a For loop. The count is then dumped into a cell, and the calculation moves onto the next value in the range.
I've currently got 95 entries into the log and the counts are running pretty slowly. As we get more quality concerns, its inevitable that the code will start to run even slower.
This is a sample of the code i'm running:
For Each cell In mnthRng
monthVal = cell.value
YearVal = cell.Offset(-1, 0).value
num = 1
Total_prjctCount = 0
For i = LBound(prjcts) To UBound(prjcts)
PrjctName = prjcts(i)
included_in_calcs = prjctYesNo(num, 1)
If included_in_calcs = "YES" Then
Total_Count = 0
For j = 8 To IDLastRow
If QCRLogSheet.Range("AI" & j) = monthVal _
And QCRLogSheet.Range("AK" & j) = YearVal _
And QCRLogSheet.Range("D" & j) = PrjctName Then
Total_Count = Total_Count + 1
Else
End If
Next j
Total_prjctCount = Total_Count + Total_prjctCount
End If
num = num + 1
Next i
cell.Offset(1, 0).value = Total_prjctCount
Next cell
Just to give you some more information on the code:
mnthRng is a cell range containing different months.
The array prjcts contains the name of the various different projects we have onsite, and allows me to sort the data out by project is someone unticks the "include in calculations" box on the dashboard
I've read that to speed up calculations of this nature, instead of looping per cell, i could add the range to an array, and do the count in the array. Unfortunately i'm not sure how i go about adding my data range into an array and then looping through it.
Any help would be much appreciated!

Answer 1

Untested:
Dim arrMonth, arrYear, arrProj
arrMonth = QCRLogSheet.Range("AI8:AI" & IDLastRow)
arrYear = QCRLogSheet.Range("AK8:AK" & IDLastRow)
arrProj = QCRLogSheet.Range("D8:D" & IDLastRow)
For Each cell In mnthRng
monthVal = cell.Value
YearVal = cell.Offset(-1, 0).Value
num = 1
Total_prjctCount = 0
For i = LBound(prjcts) To UBound(prjcts)
PrjctName = prjcts(i)
included_in_calcs = prjctYesNo(num, 1)
If included_in_calcs = "YES" Then
Total_Count = 0
For j = 1 To UBound(arrMonth, 1)
'nested if's are faster...
If arrMonth(j, 1) = monthVal Then
If arrYear(j, 1) = YearVal Then
If arrProj(j, 1) = PrjctName Then Total_Count = Total_Count + 1
End If
End If
Next j
Total_prjctCount = Total_Count + Total_prjctCount
End If
num = num + 1
Next i
cell.Offset(1, 0).Value = Total_prjctCount
Next cell