Subtraction Of Series Of Cells' / Array Values

[Rick Rothstein]

I'm using the following code

Option Explicit

Sub CTest()
    Dim r   As Long
    Dim ka, k()
 Dim i   As Long
    
    r = Range("C" & Rows.Count).End(3).Row + 1
    
    ka = Range("C3:C" & r)
    
    ReDim k(1 To UBound(ka, 1), 1 To 1)
 
    For i = 1 To UBound(ka, 1) - 1
        k(i, 1) = ka(i + 1, 1) - ka(i, 1)
    Next

    Range("O3").Resize(UBound(k, 1)) = k
End Sub

I doubt if the time difference is measurable, but given what you are doing, you do not need the k array... just do your calculations back into the ka array itself...

Sub CTest()
    Dim r   As Long
    Dim ka
    Dim i   As Long
    
    r = Range("C" & Rows.Count).End(3).Row + 1
    
    ka = Range("C3:C" & r)
    
    For i = 1 To UBound(ka, 1) - 1
        ka(i, 1) = ka(i + 1, 1) - ka(i, 1)
    Next
    Range("O3").Resize(UBound(ka, 1)) = ka
End Sub