Assigning variables in copying excel to excel file - vba

Question

I'm trying to copy cells(1,1) of excel file 1 to cells(1,1) of excel file 2.
But assuming that I've placed the name of the file I want to open in cells(2,20) and I want to assign variable j = cells(2,20) and use it in a code in copying the file. I seem to be having problems with that.
Here is my code:
Sub Copy_Workbook()
j = Cells(2, 20)
Workbooks.Open ("C:\Users\GNPOWER\Desktop\TRADERS\Jonel\practice\data fetching\" & j & ".xlsx")
Workbooks("Practice_Copy_From.xlsm").Worksheets("Sheet1").Cells(1, 1) = _
Workbooks(" & j & "&.xlsx").Worksheets("Sheet1").Cells(1, 1).Value
End Sub
Am I missing something like a declaration or what?
I'm getting subscript of range 9 when running the program.

Answer 1

You don't have to add an explicit quotation mark in the workbooks name declaration. Also there was an ampersand in front of the extension "&.xlsx" which I removed. Code would be:
Sub Copy_Workbook()
Dim j As String, wb As Workbook
j = Cells(2, 20).Value2
Set wb = Workbooks.Open("C:\Users\GNPOWER\Desktop\TRADERS\Jonel\practice\data fetching\" & j & ".xlsx")
ThisWorkbook.Worksheets("Sheet1").Cells(1, 1).Value2 = wb.Worksheets("Sheet1").Cells(1, 1).Value2
End Sub

Answer 2

you don't even need to open the "source" file
Option Explicit
Sub Copy_Workbook()
Dim pathName As String, fileName As String
fileName = Cells(2, 20).Value '<--| retrieve the file name from the currently active worksheet cell "A1"
pathName = "C:\Users\GNPOWER\Desktop\TRADERS\Jonel\practice\data fetching\" '<--| set the folder path where "source" workbooks resides
With Workbooks("Practice_Copy_From.xlsm").Worksheets("Sheet1").Cells(1, 1) '<--| reference your "target" cell
.Value = "='" & pathName & "[" & fileName & "]Sheet1'!$A$1" '<--| write a formula that references the proper cell in the proper worksheet of the proper workbook
.Value = .Value '<--| get rid of formula and leave value only
End With
End Sub