Loop through columns names : For variable = A to Z - vba

Question

is it possible to loop on column letters?
For col = A to Z
column(col:col).select
selection.copy
Next
Or am I oblige to use a function to transform letters into numbers?

Answer 1

To convert Formulas to Values:
Dim cols As Range, c As String
Set cols = UsedRange.Columns
For Each c In Split("N Q T") ' add the rest of the column letters
cols(c).Value = cols(c).Value ' or .Value2 if no dates or currencies in the range
Next
If it is every third column from column N, another approach can be:
Dim col As Range, i As Long
Set col = UsedRange.Columns("N")
For i = 1 To 17 ' to repeat 17 times
col.Value = col.Value
Set col = col.Offset(, 3)
Next

Answer 2

No need to transform letters into numbers as you can pass letters to Columns and Cells:
Columns("B") 'the same as Columns(2)
Cells(1, "B") 'same as Cells(1, 2)
However looping through letters is kind of a hassle and you'd have to transform a number into a letter first, for example using Chr(64 + Num)

Answer 3

I don't know if it take a lot of calculating time but I actually have
Columns("N:N").Select
selection.Copy
selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Columns("Q:Q").Select
selection.Copy
selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Columns("T:T").Select
selection.Copy
selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
I have 17 time this group of rows, do you think it's a huge waste of time?
EDIT
answer with the link in the comment below, thanks to #Rdster

Answer 4

I suggest one of these two solutions :
1- The Column A is the first column, and Z is the 26th column
'Declaration
Dim iFirstCol as integer
Dim iLastCol as integer
iFirstCol = 1 'the first column (A)
iLastCol = 26 'the last column (Z)
'Looping
FOR col = iFirstCol to iLastCol
Columns(col:col).Select
Selection.Copy
'....
LOOP col
2- The ASCII values of the letters A to Z are 65 to 90.
'Declaration
Dim Cols as string
Your loop can be easily transformed into:
'Looping
FOR col = 65 to 90
Cols=CHR(col) & ":" & CHR(col)
Columns(Cols).Select
Selection.Copy
'...
LOOP col
Hope this can help!