Applying VBA RIGHT to an entire column - Infinite Loop Issue - vba

Question

I have data that I am working to Parse Out that I have imported from approval emails sent in Outlook. At this point I am just importing the CreationTime and the SubjectLine.
For the subject line I am able to use the Split function to separate out most of the data. I then am left with Job Codes in Column B and Position numbers in Column C which includes the text: "Job Codes: XXXX" and the four digit job code number and "PN XXXX" and either a four digit or 6 digit position number. I am trying to use the Right functionality to loop through the entire column and reformat the column just to show only the four digit job code number for Column B and either just the 4 digit or 6 digit position number (the actual numbers) for Column C
For Job Code Column B:
Currently my code works for Shortening the Job Codes but it involves adding a column, putting the RIGHT formula in that column for the shortened Job Code, then copying and pasting the formula as values back into the column and then deleting the original column.
The problem- Works but perhaps not the most efficient with a larger data set (currently 200 rows but will have 2000 or more)
Code:
Sub ShortenJobCodes()
Application.ScreenUpdating = False
Const R4Col = "=RIGHT(RC3,4)"
Dim oRng As Range
Dim LastRow As Long
Range("B1").EntireColumn.Insert
LastRow = Cells(Rows.Count, "A").End(xlUp).Row
Set oRng = Range("B:B")
Range(oRng, Cells(LastRow, "B")).FormulaR1C1 = R4Col
Set oRng = Nothing
Columns("B").Select
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues
Range("C1").EntireColumn.Delete
Application.ScreenUpdating = True
End Sub
For Position Numbers Column C:
Currently I have mirrored the above code but added in an if statement using LEN to count if the characters are less than 8, if so then insert one RIGHT function if not insert the other RIGHT function. This also involves adding an additional column putting the RIGHT formula in that column for the shortened Position Number(Eliminating all but just the number), then copying and pasting the formula as values back into the column and then deleting the original column.
Problem - This works but seems to take forever to process and in fact looks like it is in an infinite loop. When I Esc out of it, it does add the column and then input the proper RIGHT formula (leaving just the numeric values) but the sub never seems to end, nor does it copy and paste the formulas as values or delete the original column. As noted above I realize this is likely a more efficient way to do this but I have tried a bunch of options without any luck.
I am realizing part of the loop might be due to the range itself being an entire column but I cannot find a way to stop that with the last row (even though I have a count in there).
Code:
Sub ShortenPositionNumbers()
Application.ScreenUpdating = False
Const R4Col = "=RIGHT(RC4,4)"
Const R6Col = "=RIGHT(RC4,6)"
Dim oRng As Range
Dim rVal As String
Dim y As Integer
Dim selCol As Range
Dim LastRow As Long
Range("C1").EntireColumn.Insert
LastRow = Cells(Rows.Count, "A").End(xlUp).Row
Set selCol = Range("D:D")
For Each oRng In selCol
oRng.Select
rVal = oRng.Value
If Len(oRng.Value) > 8 Then
oRng.Offset(0, -1).FormulaR1C1 = R6Col
Else
oRng.Offset(0, -1).FormulaR1C1 = R4Col
End If
Next
Set oRng = Nothing
Columns("C").Select
Selection.Copy
Selection.PasteSpecial Paste:=xlPasteValues
Range("D1").EntireColumn.Delete
Application.ScreenUpdating = True
End Sub
Major Question: Is there a way to use RIGHT/TRIM/LEN/LEFT functions to do this within a cell without having to add columns/delete columns and insert functions?

Answer 1

There are a few things you can do here to speed up your code. I'm only going to reference the second code block as you can apply similar logic to the first.
The first issue is that you create a LastRow variable but never reference it again. It looks like you meant to use this in the selCol range. You should change that line to Set selCol = Range("C1:C" & lastRow). This way, when you loop through the rows you only loop through the used rows.
Next, in the For-Each loop you Select every cell you loop through. There really isn't any reason to do this and takes substantially longer. You then create the variable rVal but never use it again. A better way to set up the loop is as follows.
For Each oRng in selCol
rVal = oRng.Value
If Len(rVal) > 8 Then
oRng.Value = Right(rVal, 6)
Else
oRng.Value = Right(rVal, 4)
End If
Next
This is much cleaner and no longer requires creating columns or copying and pasting.

Answer 2

Try this, it uses Evaluate and no loops or added columns.
Sub ShortenPositionNumbers()
Application.ScreenUpdating = False
Dim selCol As Range
Dim LastRow As Long
With ActiveSheet
LastRow = .Cells(Rows.Count, "A").End(xlUp).Row
Set selCol = .Range(.Cells(1, 3), .Cells(LastRow, 3))
selCol.Value = .Evaluate("INDEX(IF(LEN(" & selCol.Address(0, 0) & ")>8,RIGHT(" & selCol.Address(0, 0) & ",6),RIGHT(" & selCol.Address(0, 0) & ",4)),)")
End With
Application.ScreenUpdating = True
End Sub

Answer 3

Or work with arrays
Sub ShortenPositionNumbers()
Dim data As Variant
Dim i As Long
With Range("C3:C" & Cells(Rows.Count, "A").End(xlUp).Row)
data = Application.Transpose(.Value)
For i = LBound(data) to UBound(data)
If Len(data(i)) > 8 Then
data(i) = RIGHT(data(i),6)
Else
data(i) = RIGHT(data(i),4)
End If
Next
.Value = Application.Transpose(data)
End With
End Sub