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Creating a random (non-duplicated) user id number.

Posted on 2002-03-14
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Last Modified: 2010-05-02
Is there a way whereby I can create a random ID number(of 5 or plus digits - numbers or letters) in VB. As long none of them are the same.

Is there an algorithm or function I can use? I don't know if Rnd can do the trick.

Thanks

Hannes


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Question by:hannes1
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5 Comments
 
LVL 53

Accepted Solution

by:
Ryan Chong earned 800 total points
ID: 6863804
Hi,

Try this:

Dim myArray() As Long
Dim i As Long, j As Long

Private Sub Command1_Click()
    GetRandomID 100
End Sub

Private Sub GetRandomID(ByVal iRange As Long)
    Erase myArray
    Randomize
    For i = 0 To iRange - 1
        j = Format$(Int(Rnd * 100000), "00000")
        Debug.Print j
    Next i
End Sub
0
 

Expert Comment

by:pritam_dewan
ID: 6864428
i dont think u can really rely on generating unique random numbers.well u can try generating GUIDs.that will be unique globally.
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LVL 53

Expert Comment

by:Ryan Chong
ID: 6864481
sorry just not see carefully about "non-duplicated".

See this:
http://www.vbcode.com/asp/showsn.asp?theID=407

http://www.vbcode.com/asp/showsn.asp?theID=173
0
 
LVL 8

Expert Comment

by:glass_cookie
ID: 6865302
Hi!

This is the code that I gave some time ago.  Chances are, it shouldn't be duplicated:

Dim myNumber As String, temp As Integer

For i = 0 To 9

Randomize
temp = Rnd * 10
If temp \ 2 = temp / 2 Then
myNumber = myNumber & Chr(48 + Int(Rnd * 10))
Else

Randomize
temp = Rnd * 10
If temp / 2 = temp \ 2 Then
myNumber = myNumber & Chr(65 + Rnd * 26)
Else
myNumber = myNumber & LCase(Chr(65 + Rnd * 26))
End If
End If

Next i

MsgBox myNumber


The thing is, using Randomize would make it more random.  

That's it!

glass cookie : )
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Author Comment

by:hannes1
ID: 6876121
It works fine for me.

Thanks

Hannes
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