excel vba: subscript out of range - vba

Question

the vba code is:
Sub D()
Dim a As String
Dim wb As Workbook
Dim file As Variant
Dim arr1() As Variant
Dim arr2() As Variant
Dim arr3() As Variant
Dim arr() As Variant
Dim arr4() As Variant
Dim arr5() As Variant
Dim arr6() As Variant
Dim t As Integer
ActiveWorkbook.Activate
ActiveSheet.Activate
arr4 = Range("J2:J256")
arr5 = Range("K2:K256")
arr6 = Range("L2:L256")
ActiveSheet.Activate
For Row = 1 To UBound(arr4, 1)
If arr4(Row, 10) = "IS" And arr5(Row, 11) = "IS" And arr6(Row, 12) = "IS" Then
Cells(Row + 1, 13) = "UPDATE AB SET S=" & Cells(Row + 1, 6) & "WHERE C=" & Cells(Row + 1, 3) & ";"
End If
Next Row
End Sub
I am getting error as Subscript Out of range at arr4(Row,10)= when debugged.Can u help in rectifying the error so that the code may be able to function correctly.

Answer 1

I think the problem lies in your understanding of the array. You are using absolute cell references for your array (which is relative). The first index of an array, ie (1, 1), references the first cell in your range, so for Range("K2:K256") arr(1, 1) will be referencing the value of cell "K2", arr(10, 1) will be referencing the value of cell "K11", etc.
As LMM9790 points out, if you wanted to keep your code structure as is then it could simply be written as:
If arr4(Row, 1) = "IS" And arr5(Row, 1) = "IS" And arr6(Row, 1) = "IS" Then
Cells(Row + 1, 13) = "UPDATE AB SET S=" & Cells(Row + 1, 6) & "WHERE C=" & Cells(Row + 1, 3) & ";"
End If
However, I'd have to ask why you need so many arrays, one for each column? Given that arr4, 5 and 6 all have the same row dimension, you could simply have one array that contains all of the columns. Moreover, you could have one array for the entire dataset, amend the applicable value, then rewrite the array to the Worksheet.
Elsewhere the code is a little odd. Is there a reason, for example, that you would activate an active sheet and book? You also have several unused variables - are you intending to use these later?
Your whole code could be simplified to this:
Sub D()
Dim ws as Worksheet
Dim r As Integer
Dim v As Variant
Set ws = ActiveWorkbook.Worksheets("Sheet1") 'name as appropriate
v = ws.Range("C2:M256").Value2
For r = 1 To UBound(v, 1)
If r < Ubound(v, 1) then
If v(r, 8) = "IS" And v(r, 9) = "IS" And v(r, 10) = "IS" Then
v(r + 1, 11) = "UPDATE AB SET S=" & v(r + 1, 4) & _
" WHERE C=" & v(r + 1, 1) & ";"
End If
End If
Next
'...
ws.Range(("C2:M256").Value = v
End Sub

Answer 2

Regarding the out of range error, since arr4, arr5 and arr6 only contain one column you cannot access for example the 10th column of them (which is done in your code by arr4(Row, 10). Does you code work as wanted if you use the following?
Sub D()
Dim a As String
Dim wb As Workbook
Dim file As Variant
Dim Row As Integer
Dim arr1() As Variant
Dim arr2() As Variant
Dim arr3() As Variant
Dim arr() As Variant
Dim arr4() As Variant
Dim arr5() As Variant
Dim arr6() As Variant
Dim t As Integer
ActiveWorkbook.Activate
ActiveSheet.Activate
arr4 = Range("J2:J256")
arr5 = Range("K2:K256")
arr6 = Range("L2:L256")
For Row = 1 To UBound(arr4, 1)
If arr4(Row, 1) = "IS" And arr5(Row, 1) = "IS" And arr6(Row, 1) = "IS" Then
Cells(Row + 1, 13) = "UPDATE AB SET S=" & Cells(Row + 1, 6) & "WHERE C=" & Cells(Row + 1, 3) & ";"
End If
Next Row
End Sub