excel vba random
'VBA has the Rnd() function which returns a random single floating point value
'between 0 and 1, but not including 1.
MsgBox Rnd '<--displays something like 0.74323
'To generate integer values between two integer numbers, use the following formula:
'Int((max - min + 1) * Rnd + min)
'For example, to generate random integers between 11 and 14:
MsgBox Int((14 - 11 + 1) * Rnd + 11) '<--displays 11 or 12 or 13 or 14
'------------------------------------------------------------------------------
'Note: If min is ONE for the above range to randomly select from, then
' the formula can be shortened to: Int(Rnd * max + 1):
MsgBox Int(Rnd * 4 + 1) '<--randomly displays 1 or 2 or 3 or 4
'Note: If min is ZERO for the above range to randomly select from, then
' the formula can be shortened to: Int(Rnd * (max + 1)):
MsgBox Int(Rnd * (3 + 1)) '<--randomly displays 0 or 1 or 2 or 3
'------------------------------------------------------------------------------
'Note: Each time the Rnd() function is called a different random single floating
' point value will be returned. But Rnd() is likely to produce
' the same SEQUENCE of random values if the procedure containing
' the multiple calls to the Rnd() function is accessed later.
'
' To ensure that the routine procuces a fresh sequence of random
' numbers when the routine is later called again, use the VBA
' Randomize statement once:
Sub RandomSequence()
Randomize
Debug.Print Rnd, Rnd, Rnd
End Sub
'Reference:
https://docs.microsoft.com/en-us/office/vba/language/reference/user-interface-help/randomize-statement