fill one dimensional dynamic array - excel

Question

I have code like this.
Dim sums() As Single
dim n as integer
For n = 0 To ActiveCell.Value - 2
sums(n) = Abs(Application.WorksheetFunction.SumIf(Range(Cells(i + m, 6), Cells(j - 1, 6)), Range("F" & i + m).Value, Range(Cells(i + m, 17), Cells(j - 1, 17))))
Next n
I am getting an error message for sums(n)= .... I would like to fill array with values according to formula. E.G I have in activecell value 3, then I would like to have array with 2 values like sums(0) = abs(sumif..) and sums(1)= abs(sumif..).
I tried to calculate the formula without an array as sum1 = formula and it worked, but as soon as I changed it to the array because sometimes I will have there 2, 3 an more values in it, it doesn't work.

Answer 1

try the below changes:
Option Explicit
Sub sums_()
Dim sums() As Single
Dim n As Integer
Dim i As Integer
Dim m As Integer
Dim j As Integer
'assign the values or range of values for i,m,j
ReDim sums((ActiveCell.Value - 2) + 1)
For n = 0 To ActiveCell.Value - 2
sums(n) = Abs(Application.WorksheetFunction.SumIf(Range(Cells(i + m, 6), Cells(j - 1, 6)), Range("F" & i + m).Value, Range(Cells(i + m, 17), Cells(j - 1, 17))))
Next n
End Sub

Answer 2

You need to size your array first. Use Redim to do so before your loop:
Redim sums(0 to ActiveCell.Value - 2)
For n = 0 To ActiveCell.Value - 2
...
You can use Redim multiple times in your code, but note that if you want to keep the content of the array, you have to use Redim preserve and that is rather slow because the complete array is rebuild. So you should avoid to use Redim preserve within a loop.