Populate correct headers from closed workbook - excel

Question

I have been working on the problem below for a while now and I got a very basic version to work without error handling. My goal is to have this macro run from the personal macro workbook.
I am importing pipe delimited text files from various sources and none of the formatting in the headers match (some providers decided to play around with the entire layout). With this issue at hand, I created an Excel workbook named Reference(aka Map) with the incoming files layout and standardized/corrected columns' name formatting.
The good news for me is, the file ID will always be on column A. I have about 65 files that need to processed each month so I need to minimize all possible steps and therefore need to have the Reference workbook closed.
With this, I looked around online and put together most of the solution to pull in the new headers based on the ID located in A3. Yet a dilemma still exists, sometimes the ID on A3 will not exist on the Reference workbook - I need to have the vlookup move down to the next row until the result does not equal #N/A or 0 or blank.
At this point I got the 'Do Loop Until' to find the correct row for the first match - works perfectly with out any code following it.
As soon as the vlookup finds a row with an existing ID, then run the snippet below to populate the remaining headers. The only side effect of the next step is, for some reason rID offsets +1 row, undoing the 'Do Loop until' if the final row does not contain a matching ID.
'> Populate remining headers
For Each cell In rng1
cell.Value = ("=VLOOKUP(" & cID & rID & "," & map & "," & i & ",FALSE)")
i = i + 1
Next
This is what I have so far:
Sub DAc_lookup_headers()
Dim wb1 As Workbook 'Current text/file
Dim map As String 'reference Map
Dim cID As String 'wb1 look up column A
Dim rID As String 'wb1 starting row number
Dim rng1 As Range 'wb1 Collection header range
Dim i As Long 'Index number per cell in range
Set wb1 = ActiveWorkbook
Set rng1 = wb1.ActiveSheet.[A1:G1]
map = ("'C:\Users\x165422\Desktop\New folder\[Reference.xlsx]Ref'!$A$1:$I$13")
rID = 3 'Row where ID is - will increment + 1 if not found
cID = "A" 'Column where ID is
i = 3 'Starting vlookup Index number - to increment per cell in range
'>Look for ID until value is found
Do
wb1.ActiveSheet.[a1].Value = ("=VLOOKUP(" & cID & rID & "," & map & "," & i & ",FALSE)")
rID = rID + 1
Loop Until wb1.ActiveSheet.[a1].Text <> "#N/A" Or "0"
'> Populate remining headers
For Each cell In rng1
cell.Value = ("=VLOOKUP(" & cID & rID & "," & map & "," & i & ",FALSE)")
i = i + 1
Next
'> Convert to values
With rng1
.Value = .Value
End With
End Sub

Answer 1

I'll try to help a bit, because you show effort to learn. I will give you some useful tips regarding overall VBA coding and also regarding your issues. Please try to remember them.
It's difficult to read your code, because your variables are poorly named. In VBA there is a difference between a cell and it's value. In your code you have rng1 and rng2. I see that currently rng1 represents cell's value, and rng2 - a cell itself. I'm not sure if you intentionally did that, but now you will understand it. IF you mean a cell itself, then naming the variable rng2 is well understood. But IF you mean cell's value, naming the variable rng1 is misleading. That's only for being able to read the code more easily. Since you defined this variable as string, I suspect that you are expecting it to receive a value of string type. So, you should name your variable something in relation with it's type, i.e. something beginning with str... or s... which would mean that this variable is of string type, e.g. strValue or sID. preferable approach is to use str, as s could be confused with single type (there is such data type in VBA too). You should apply this logic to every variable that you use. String - str..., long - lng..., integer - int..., double - dbl..., boolean - bln..., etc. One type is kind of specific and you use it here too. It's the object type. Objects are not only objects, they are broken down to many different types, and within your code you use range and workbook objects too. You can name them o... or obj..., or usually it's better to use a more specific name, like rng... (for range) or wb... (for workbook). Usual data type variables take values without Set clause, while objects always need Set in order to be associated with some actual object, like range, workbook, sheet, etc. In your code we see wb2 variable which is a string. As now you know, that's not good.
So, in this case you should rename rng1 if you expect it to be string and not a range and learn to always use this naming convention. Same goes to wb2.
Always use Option Explicit as the topmost line in your code module, before all of the subs. This simply prevents from typos. And that's actually an indispensable line. I always use it and everyone should. After doing this, I see that you code will not run, because cell variable is not defined. Use Dim cell As Range, because cell is actually an object of range type. Set is omitted in this case, because For Each ... In ... Next loop does that for you.
Now your actual problems.
You would find Worksheet.UsedRange useful for determining columns count. That represents the area in a sheet from A1 to the last used cell (that's actually an intersection of the last used column and the last used row). Given that your data spans from the column A and when it ends there are no more data to the right not belonging to any column, you might use ActiveSheet.UsedRange.Columns.Count to get the number of columns in your UsedRange and hopefully in your sheet.
I mentioned UsedRange first, because I wanted you to get acquainted with it. We'll use it to solve the problem of vlookup. So the first step that I would suggest before the vlookup is to find the cell with your ID. We should first dim variables that we'll use, e.g. rng3:
Dim rng3 As Range
Then my suggestion is to find the cell with ID looping through cells in the column A, beginning A3, but not looping until the end of the column, because there are 1m rows, but until we reach the last actually used row:
For Each cell In wb1.ActiveSheet.Range("A3:A" & wb1.ActiveSheet.UsedRange.Rows.Count)
If cell <> "" Then
Set rng3 = cell
Exit For 'we found the value, no need to continue looping, so we exit the For loop
End If
Next 'there is no need to write "cell" after "Next", because VBA knows which loop it is in.
Now, that we have the cell where your ID is, we can put lookups in:
i = 2 'Starting vlookup Index number per cell in range
For Each cell in rng2
cell.Value = "=VLOOKUP(" & rng3.Address & "," & wb2 & "," & i & ",FALSE)" 'again, wb2 is not a nice name for String variable
i = i + 1
Next
I hope here are no typos, as I have not tested it. However, I've double checked the code, it looks ok.

Answer 2

I got it to work with:
Sub DAc_lookup_headers()
Dim wb1 As Workbook 'Current text/file
Dim map As String 'reference Map
Dim cID As String 'wb1 look up column A
Dim rID As String 'wb1 starting row number
Dim rng1 As Range 'wb1 Collection header range
Dim i As Long 'Index number per cell in range
Set wb1 = ActiveWorkbook
Set rng1 = wb1.ActiveSheet.[A1:G1]
map = ("'C:\Users\x165422\Desktop\New folder\[Reference.xlsx]Ref'!$A$1:$I$13")
rID = 2 'Row where ID is - will increment + 1 if not found
cID = "A" 'Column where ID is
i = 3 'Starting vlookup Index number - to increment per cell in range
'>Look for ID until value is found
Do
rID = rID + 1
wb1.ActiveSheet.[a1].Value = ("=VLOOKUP(" & cID & rID & "," & map & "," & i & ",FALSE)")
Loop Until wb1.ActiveSheet.[a1].Text <> "#N/A" Or "0"
'> Populate remining headers
For Each cell In rng1
cell.Value = ("=VLOOKUP(" & cID & rID & "," & map & "," & i & ",FALSE)")
i = i + 1
Next
'> Convert to values
With rng1
.Value = .Value
End With
End Sub