Search/Replace in One Column Impacting Entire Worksheet - excel

Question

In Column L (only) I want to replace any instance of data with "True" regardless of what was originally in any of the Column L cells. The code I tried was:
With ActiveSheet
intLastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
Let strSelectRange = "L2" & ":" & "L" & intLastRow
Range(strSelectRange).Select
Cells.Replace What:="*", Replacement:="True", LookAt:=xlPart _
, SearchOrder:=xlByColumns, MatchCase:=False, SearchFormat:=False, _
ReplaceFormat:=False
End With
First, I used .Rows.Count, "A" because in that column every row has data so I know how many rows to go down in Column L. In Column L many cells will be blank.
When I run this, every cell in the entire worksheet that has anything in it, is changed to True, not just the data in Column L.
Another method I tried was:
Range("L2:L1200").Select
Selection.Replace What:="*", Replacement:="True", LookAt:=xlPart, _
SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
ReplaceFormat:=False
Range("A1").Select
What I don't like about this is that I picked L1200 as the number of rows just to be sure I'd search farther than the actual last row that can contain data. I'm worried that this method might cause some kind of problem at some point.
What I'd really like to know is what I'm doing wrong in the first code example.
Thanks for any help you can offer!!!

Answer 1

Search & Replace in Column
Use Option Explicit always, to quicker learn about the occurring
errors and to be forced to declare variables.
You should always declare your rows as Long.
When you use the With statement you use the dots on everything, even
on .Range and .Cells etc. The code might work in this case
(ActiveSheet) anyway, but it is incorrect.
Avoid the use of ActiveSheet, use the worksheet name.
Avoid the use of Select. There are many posts (articles) about this.
When ever you use Cells without anything behind it, it refers to all the
cells in the worksheet.
The first thing in the Replace function (Find function) is the range
where you're going to Replace (Find, Search). It can be a column, it
can be Cells or just a smaller range.
The Code
Sub SROneColumn()
Const cVntLRColumn As Variant = "A" ' Last Row Column Letter/Number
Const cVntCriteria As Variant = "L" ' Criteria Column Letter/Number
Const cLngFirstRow As Long = 2 ' First Row Number
Const cStrReplace As String = "True" ' Replace String
Dim lngLastRow As Long ' Last Row Number
Dim strSelectRange As String ' Select Range Address
With ActiveSheet
lngLastRow = .Cells(.Rows.Count, cVntLRColumn).End(xlUp).Row
strSelectRange = .Range(.Cells(cLngFirstRow, cVntCriteria), _
.Cells(lngLastRow, cVntCriteria)).Address
.Range(strSelectRange).Replace What:="*", Replacement:=cStrReplace, _
LookAt:=xlPart, SearchOrder:=xlByColumns, MatchCase:=False
End With
End Sub
An interesting way to use a worksheet without the use of an object variable:
Sub SRSheet()
Const cStrSheet As Variant = "Sheet1" ' Worksheet Name/Index
With ThisWorkbook.Worksheets(cStrSheet)
End With
End Sub

Answer 2

Range(strSelectRange).Select
selects a range (though best to avoid Select) but then your code does nothing with that selection because Cells is the entire sheet.
Maybe you want instead:
Range(strSelectRange).Replace What:="*", Replacement:="True", LookAt:=xlPart