Category: Excel

If you’re getting into Excel macros and have fooled around with the macro recorder you may notice that the resulting code is very rigid: it only works on the exact range of cells you had selected for example (among other drawbacks). In many cases you want your code to adapt to the size of the data in a sheet, and for this you need to determine the boundaries of the range.

.UsedRange Property

If you’ve done a search you may have come across this approach already. .UsedRange.Rows.Count will usually give the right result if you’re looking for the last used row on a particular sheet, but not always. For whatever reason, this property is not always current – sometimes it is possible to clear the contents of a row without causing this to update, giving an incorrect result. Saving the document (and probably some other actions) will cause this to be updated, but I don’t consider it to be reliable enough to base further logic on.

.End(xlUp).row

This approach is the equivalent of putting your cursor in a cell and pushing CTRL+UP. If you do this on the very last row of a sheet, the cell that your cursor lands on will be the last one in that column. This works reliably, but only gives a result for one column, not the entire sheet. If you put this together with a loop and repeat it for all columns (or a reasonable number) you can reliably retrieve the last used row on a sheet.

The function: getLastRow()

Putting this all together, an easy to use function can be made that returns the last row number on a sheet or in a specific column.

• If called with no parameters it will return the last used row in the first 100 columns of the active sheet.
• The optional sheetName parameter is useful to reference a sheet other than the active one, or if you can’t guarantee which sheet is active when the function is called.
• The second optional parameter, colNum, can be used if you want to know the last used row in a specific column.

Examples

Here are some examples of how this works with the sample sheet below:

getLastRow() = 8 'from the active sheet
getLastRow("Fruit") = 8 'even when a different sheet is active
getLastRow(,3) = 6 'from the active sheet
getLastRow("Fruit", 3) = 6 'even when a different sheet is active
getLastRow("Fruit", 4) = 1 'this column is empty
getLastROW("Vegetables") = 0 'this sheet name is invalid

And finally, the function itself:

Function getLastRow(Optional sheetName As String, Optional colNum As Long) As Long
'by Elliot 7/22/20 www.elliotmade.com
'this function will return the last used row on a sheet or a single row
'if no sheet name is specified it will use the active sheet
'if no column is specified it will find the last row in any of the first 100 columns
'two assumptions are made: the file type is .xlsx or similar that supports ~1M rows
'and the sheet is in the active workbook

'a zero returned means that there was a failure

Dim i As Long
Dim j As Long
Dim curLastRow As Long

'check for valid inputs first, return zero if there is a problem
If colNum < 0 Or colNum > 16384 Then GoTo abort

If sheetName <> "" Then
    For j = 1 To Worksheets.Count
        If Worksheets(j).Name = sheetName Then GoTo sheetOK
    Next j
    GoTo abort 'specified sheet name was not found
sheetOK:
End If

If sheetName = "" Then sheetName = ActiveSheet.Name

'if no problem, find the last row
If colNum = 0 Then
For i = 1 To 100
    curLastRow = Worksheets(sheetName).Cells(1048575, i).End(xlUp).Row
    If curLastRow > getLastRow Then getLastRow = curLastRow
Next i

Else
    curLastRow = Worksheets(sheetName).Cells(1048575, colNum).End(xlUp).Row
End If

abort:

getLastRow = curLastRow

End Function

If you found this useful, or if you have a problem this might help you solve, let me know!

I saw this: https://hackaday.com/2020/04/13/john-horton-conway-creator-of-conways-game-of-life-has-died/, decided that I would try to write his game myself. This was just for fun and it isn’t optimized for anything really, but it might be useful to check out if you are getting into macros for Excel and need to read/update cells in a worksheet.

If you’re not comfortable downloading an .xlsm from (which is wise), the code below can just be pasted in an empty module. Make sure to name a sheet in your workbook “Life”, type in a number in cell B9 (or hardcode it), and add buttons to call the subs if you want.

The black cells are 1’s, white cells are 0’s. Might be interesting to tweak this so it generates QR codes and see where it takes you!

Option Explicit

'by Elliot (elliotmade.com) 4/14/2020
'Conway's game of life

'there is no input validation, and literally no optimization for anything
'wrote this purposely without looking at any examples other than a description of the rules, just for fun

'rules (from wikipedia):
'    Any live cell with two or three live neighbors survives.
'    Any dead cell with three live neighbors becomes a live cell.
'    All other live cells die in the next generation. Similarly, all other dead cells stay dead.

Dim xMax As Long
Dim yMax As Long

Dim x As Long
Dim y As Long

Dim xOffset As Long 'so it doesn't have to occupy the top and left cells
Dim yOffset As Long

Dim ws As Worksheet
Dim ticks As Long
Dim maxTicks As Long

Dim currentGrid() As Byte
Dim nextGrid() As Byte


Sub initialize()
'read in the initial state

xMax = 40
yMax = 40
ticks = 0

xOffset = 3
yOffset = 3

Set ws = Worksheets("Life")

ReDim currentGrid(1 To xMax, 1 To yMax)
ReDim nextGrid(1 To xMax, 1 To yMax)

For y = 1 To yMax
    
    For x = 1 To xMax
        currentGrid(x, y) = ws.Cells(y + yOffset, x + xOffset)
    Next x
Next y

maxTicks = ws.Cells(9, 2).Value


Debug.Print "Initialized"

End Sub

Sub clear()
    Call initialize
    ws.Range(ws.Cells(1 + yOffset, 1 + xOffset), ws.Cells(yMax + yOffset, xMax + xOffset)).Value = 0
    Call initialize
    Call output
    Debug.Print "Cleared"

End Sub

Sub tick()
'really should do initialize if the variables aren't populated...

Dim countNeighbors As Integer

For y = 1 To yMax
    For x = 1 To xMax
        countNeighbors = 0
        'top neighbor
        If y > 1 Then
            countNeighbors = countNeighbors + currentGrid(x, y - 1)
        End If
        'bottom neighbor
        If y < yMax Then
            countNeighbors = countNeighbors + currentGrid(x, y + 1)
        End If
        'left neighbor
        If x > 1 Then
            countNeighbors = countNeighbors + currentGrid(x - 1, y)
        End If
        'right neighbor
        If x < xMax Then
            countNeighbors = countNeighbors + currentGrid(x + 1, y)
        End If
        
        'top left neighbor
        If x > 1 And y > 1 Then
            countNeighbors = countNeighbors + currentGrid(x - 1, y - 1)
        End If
        
        'top right neighbor
        If x < xMax And y > 1 Then
            countNeighbors = countNeighbors + currentGrid(x + 1, y - 1)
        End If
        
        'bottom right neighbor
        If x < xMax And y < yMax Then
            countNeighbors = countNeighbors + currentGrid(x + 1, y + 1)
        End If
        
        'bottom left neighbor
        If x > 1 And y < yMax Then
            countNeighbors = countNeighbors + currentGrid(x - 1, y + 1)
        End If
        
        If currentGrid(x, y) = 1 And (countNeighbors = 2 Or countNeighbors = 3) Then
            nextGrid(x, y) = 1
        ElseIf currentGrid(x, y) = 0 And countNeighbors = 3 Then
            nextGrid(x, y) = 1
        Else
            nextGrid(x, y) = 0
        End If
        
    Next x
Next y



currentGrid = nextGrid
Call output
ticks = ticks + 1

End Sub


Sub output()

Application.ScreenUpdating = False

For y = 1 To yMax
    
    For x = 1 To xMax
        ws.Cells(y + yOffset, x + xOffset).Value = nextGrid(x, y)
        If nextGrid(x, y) = 1 Then
            ws.Cells(y + yOffset, x + xOffset).Interior.ColorIndex = 1
            ws.Cells(y + yOffset, x + xOffset).Font.Color = vbBlack
        Else
            ws.Cells(y + yOffset, x + xOffset).Interior.ColorIndex = 2
            ws.Cells(y + yOffset, x + xOffset).Font.Color = vbWhite
        End If
    Next x
Next y

Application.ScreenUpdating = True
DoEvents

End Sub


Sub run()
Dim a As Long
'would be neat to end early if no changes occur between ticks...

Call initialize

If ticks = maxTicks Then
    MsgBox "Tick limit " & maxTicks & " reached"
    Exit Sub
End If

For a = 0 To maxTicks
    If WorksheetFunction.Sum(currentGrid) = 0 Then
        MsgBox "No live cells after " & ticks & " ticks"
        Exit Sub
    End If
    Call tick
Next a

End Sub

Sub randomize()
    Call initialize
    ws.Range(ws.Cells(1 + yOffset, 1 + xOffset), ws.Cells(yMax + yOffset, xMax + xOffset)).FormulaR1C1 = "=RANDBETWEEN(0,1)"
    ws.Calculate
    ws.Range(ws.Cells(1 + yOffset, 1 + xOffset), ws.Cells(yMax + yOffset, xMax + xOffset)).Value = ws.Range(ws.Cells(1 + yOffset, 1 + xOffset), ws.Cells(yMax + yOffset, xMax + xOffset)).Value
    ws.Range(ws.Cells(1 + yOffset, 1 + xOffset), ws.Cells(yMax + yOffset, xMax + xOffset)).Interior.ColorIndex = 0
    ws.Range(ws.Cells(1 + yOffset, 1 + xOffset), ws.Cells(yMax + yOffset, xMax + xOffset)).Font.Color = vbBlack
End Sub