Loop columns using VBA - excel

Question

I want to loop through columns.
I'm not sure about the range. Should I use normal range where we have the alphabets as columns?
I tried different codes. For example:
Sub copytest()
Dim x As Workbook
Dim j As Integer, i As Integer
Application.ScreenUpdating = False
Workbooks.Open ("D:\test\COMP.xlsx")
i = 3
For j = 3 To 14
Sheets("Compliance").Range(Cells(18, i), Cells(30, i)).Copy
Windows("KP.xlsm").Activate
Sheets("MOH").Range(Cells(12, j), Cells(24, j)).PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
i = i + 2
Next j
x.Close
End Sub

Answer 1

You can use numbers for columns. Let's say you want to loop through first 5 rows and first 5 columns then you can write it as
For i = 1 To 5 '<~~~ Rows
For j = 1 To 5 '<~~~ Columns
With ThisWorkbook.Cells(i, j)
'~~> Do something
End With
Next j
Next i
In Excel 2013, the last column is XFD which is column number 16384.
A - 1
B - 2
C - 3
.
.
and so on...
XFD - 16384
If you would like to loop using Column Names then you can use it as such
Dim ColName As String
For i = 1 To 5 '<~~~ Rows
For j = 1 To 5 '<~~~ Columns
ColName = Split(Cells(, j).Address, "$")(1)
With ThisWorkbook.Range(ColName & i)
'~~> Do something
End With
Next j
Next i

Answer 2

an alternative for looping though columns is a For Each cell in my1RowRange loop, where
cell is a single-cell Range object that loops over my1RowRange Range
my1RowRange must be a 1-Row Range
besides that, your code has some major flaws:
your range references use simple Cells(...) reference without any explicit worksheet and workbook reference before them
so that they keep referencing the active worksheet in the active workbook
and this is no good since during your loop you only seem to keep changing the right workbook while you're actually only changing it once at the beginning (Windows("KP.xlsm").Activate) and then it always remains the only referenced workbook
avoid Activate/ActiveXXX (as well as Select/Selection) coding, since
it's error prone, like it proved to be right here, since it most likely lead you to loose control over actual active workbook/worksheet
it's time consuming and gets screen flickerings
so consider the following refactoring of your code:
Option Explicit
Sub copytest()
Dim i As Long
Dim compWb As Workbook
Dim compRng As Range, cell As Range
Set compWb = Workbooks.Open "D:\test\COMP.xlsx" '<--| set the workbook to open to a specific variable of 'Workbook' type
With compWb.Worksheets("Compliance") '<--| refer to "compliance" worksheet of the "right" (you're explicitly referencing it!) workbook
Set compRng = .Range(.Cells(18, 3), .Cells(30, 3)) '<--| set the "source" range: all the dots means we're referencing the object after the last "With" statement
End With
i = 3
With Workbooks("KP.xlsm").Worksheets("MOH") '<--| refer to "MOH" worksheet of "KP" workbook
For Each cell In .Range(.Cells(12, 3), .Cells(12, 14)) '<--| loop through cells of a 1-row range of the referenced worksheet: this means looping through columns!
cell.Resize(13).Value = compRng.Offset(, i - 3).Value '<--| paste values while offsetting the "souce" range columns (first iteration with offset=0)
i = i + 2
Next cell
End With
compWb.Close '<--| close the opened workbook
End Sub

Answer 3

Sub Columns()
Dim rng As Range
Dim col As Range
Sheets("Sheet1").Select 'make shure its in the correct sheet
Set rng = Range("C3:G6") 'select the range of the whole table
For Each col In rng.Columns 'this performs a tasks column by column
'Do Something
col.Select
Selection.RemoveDuplicates Columns:=1, Header:=xlNo
'end something
Next col 'move to next column
End Sub