VBA Excel - passing an array into a function - excel

Question

I want to write a function in which I can include an array. I imagine that the function will work like the function NPV, we have 3 ways of specifying the syntax in the formula bar:
1) NPV(0.5, A1:A5)
2) NPV(0.5, A1, A2, A3, A4, A5)
3) NPV(0.5, {10, 20, 23, 25, 27})
Where 10, 20, 23, 25, 27 are the value in range A1:A5.
And here is my function in VBA:
Function MyNpv(r As Double, Flows As Variant)
Dim i, n As Integer
Dim p As Double
n = Application.Count(Flows)
For i = 1 To n
p = p + Flows(i) / (r + 1) ^ i
Next i
MyNpv = p
End Function
However, my own function can only work like:
MyNpv(0.5, A1:A5)
Is there anyway that I can declare my array so that it would work flexibly like the function NPV?
Thanks.

Answer 1

Use a ParamArray, Loop that to test what is in each part of the array and then adjust accordingly:
Function MyNpv(r As Double, ParamArray Flows() As Variant)
Dim FlowsPart As Variant
Dim p As Double
p = 0#
Dim k As Long
k = 1
For Each FlowsPart In Flows
Dim arr As Variant
arr = FlowsPart
Dim x As Long
x = -1
Dim y As Long
y = -1
On Error Resume Next
x = UBound(arr, 2)
y = UBound(arr)
On Error GoTo 0
Dim j As Long
Dim i As Long
If x >= 0 And y >= 0 Then
For i = LBound(arr, 1) To UBound(arr, 1)
For j = LBound(arr, 2) To UBound(arr, 2)
p = p + arr(i, j) / (r + 1) ^ k
k = k + 1
Next j
Next i
ElseIf y >= 0 Then
For j = LBound(arr) To UBound(arr)
p = p + arr(j) / (r + 1) ^ k
k = k + 1
Next j
Else
p = p + arr / (r + 1) ^ k
k = k + 1
End If
Next FlowsPart
MyNpv = p
End Function