How can I randomly select a number of cells and display the contents in a message box?

Question

I have a list of ID numbers 1101-1137 in cells A1-A37. I would like to click a button to randomly select 20 of these, with no repetitions, and display them in a message box.

Answer 1

I've added a little to one line in your code... the line is now:

strString = strString & vbCrLf & Cells(idx(i), 1).Value

the full code is:

Private Sub CommandButton1_Click()

Const nItemsToPick As Long = 20
Const nItemsTotal As Long = 37

Dim rngList As Range
Dim idx() As Long
Dim varRandomItems() As Variant
Dim i As Long
Dim j As Long
Dim booIndexIsUnique As Boolean

Set rngList = Range("A1").Resize(nItemsTotal, 1)

ReDim idx(1 To nItemsToPick)
ReDim varRandomItems(1 To nItemsToPick)
For i = 1 To nItemsToPick
    Do
        booIndexIsUnique = True ' Innocent until proven guilty
        idx(i) = Int(nItemsTotal * Rnd + 1)
        For j = 1 To i - 1
            If idx(i) = idx(j) Then
                ' It's already there.
                booIndexIsUnique = False
                Exit For
            End If
        Next j
        If booIndexIsUnique = True Then
        strString = strString & vbCrLf & Cells(idx(i), 1).Value
            Exit Do
        End If
    Loop
    varRandomItems(i) = rngList.Cells(idx(i), 1)

  Next i
    Msg = strString
    MsgBox Msg
' varRandomItems now contains nItemsToPick unique random
' items from range rngList.

End Sub

So rather than returning the number, it uses the number returned to look at the value on the row that it relates to.