call dictionary from one sub to another in VBA - excel

Question

I'm stuck with a problem when I'm working with a dictionary in VBA. The reason why I want to work with a dictionary and a do-while loop is because I have variables with different length, that I want to loop through.
First I want to give the dic keys and and items.
The reason why I skip one col for each loop is because each series has a col with dates and then a col with prices. If it is possible I want to capture the dates that match the prices in the same dictionary.
Sub opg1(dicSPX As Object)
Dim i As Integer, m As Integer
Dim varColLeng As Variant
Set dicSPX = CreateObject("Scripting.Dictionary")
m = 10
Sheets("Data").Activate
ReDim intCol(1 To nCol)
'opretter dictionary
ReDim n(1 To m)
Do While n <> ""
For i = 1 To mn
' redim preserve IntColLen
dicSPX.Add Cells(1, 2 + ((i - 1) * 2)).Value, Range(Cells(9, 2 + ((i - 1) * 2)), Cells(n, 2 + ((i - 1) * 2))).Value
Next i
Loop
End Sub
then I want to execute a procedure for all keys in my dic. I want to compute returns in different time series.
However, when I call the dic, to the sub Returns() I get an error (Compile error: Variable not defined). I'm new to dictionaries and I probably missed a small detail.
Sub Returns()
Call opg1(dicSPX)
Dim dicSPX As New Scripting.Dictionary
Dim varKey As Variant, varArr As Variant
For Each varKey In dicSPX
varArr = dicSPX(varKey)
For i = LBound(varArr, 1) To UBound(varArr, 1)
For j = LBound(varArr, 2) To UBound(varArr, 2)
' varReturns(i,j) = compute the return here
Next
Next
Next
Any suggestions? I hope the question is clear.
Thank you

Answer 1

It should be clear which variable is not defined by the line which is highlighted after the error is thrown. At a quick glance I can tell that you didn't define i or j:
Sub Returns()
Dim dicSPX As New Scripting.Dictionary
opg1(dicSPX)
Dim varKey As Variant
For Each varKey In dicSPX
Dim varArr As Variant
varArr = dicSPX(varKey)
Dim i As Long
For i = LBound(varArr, 1) To UBound(varArr, 1)
Dim j As Long
For j = LBound(varArr, 2) To UBound(varArr, 2)
varReturns(i,j) = compute the return here
Next
Next
Next
End Sub
You should always explicitly define each variable, one line at a time, right before they are used. This way the declaration is always near the usage so you can see it on the same page.
You should also make opg1 a function that returns a dictionary. That would clarify your intent. Passing a variable by reference makes it harder to tell how the program works to the reader.