Article ID: 213290 - Last Review: November 23, 2006 - Revision: 3.5

XL2000: How to Create Unique Random Integers Between Two Numbers

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This article was previously published under Q213290

SUMMARY

In Microsoft Excel, you can create a Microsoft Visual Basic Sub procedure (macro) to create a list of unique (non-repeating) random integers between two other numbers.

This articles describes a sample macro that prompts the user for a starting integer and an ending integer, prompts the user to input the number of random numbers to generate, and then generates a list of unique integers on the active worksheet.

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MORE INFORMATION

Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs.
If you have limited programming experience, you may want to contact a Microsoft Certified Partner or Microsoft Advisory Services. For more information, visit these Microsoft Web sites:

Microsoft Certified Partners - https://partner.microsoft.com/global/30000104 (https://partner.microsoft.com/global/30000104)

Microsoft Advisory Services - http://support.microsoft.com/gp/advisoryservice (http://support.microsoft.com/gp/advisoryservice)

For more information about the support options that are available and about how to contact Microsoft, visit the following Microsoft Web site:http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS (http://support.microsoft.com/default.aspx?scid=fh;en-us;cntactms) To create and run the macro described in the "Summary" section, follow these steps:

Start Excel, and then Press ALT+F11 to start the Visual Basic editor.
On the Insert menu, click Module.

Type the following code in a module sheet:

Option Explicit

Sub Unique_Numbers()
   Dim x As Long, y As Long, z As Long, tempnum As Long
   Dim flag As Boolean
   Dim i As Integer
   Dim foundCell As Range
   Application.ScreenUpdating = False
   x = Application.InputBox("Enter starting Random Number" _
      , "Random Number Generation", 1, , , , , 1)
   y = Application.InputBox("Enter ending Random Number" _
      , "Random Number Generation", 1000, , , , , 1)
   z = Application.InputBox("How many random numbers would" _
      & "you like to generate (<15000)?" _
          , "Random Number Generation", 100, , , , , 1)
   If z = 0 Then Exit Sub
   If z > 15000 Then z = 15000
   If z > y - x + 1 Then
       MsgBox "You specified more numbers to return than " _
         & "are possible in the range!"
       Exit Sub
   End If
   Randomize
   Cells(1, 1) =  Int((y - x + 1) * Rnd + x)
   For i = 2 To z
       Do
           flag = False
           Randomize
           tempnum = Int((y - x + 1) * Rnd + x)
           Set foundCell = Range("a1", _
                  Range("a1").End(xlDown).Address).Find(tempnum)
           If Not (foundCell Is Nothing) Then
               flag = True
           End If
       Loop Until Not flag
       Cells(i, 1) =  tempnum
   Next
End Sub

Press ALT+F11 to return to Excel.
On the Tools menu, point to Macro, and then click Macros.
In the Macro name list, click Unique_Numbers, and then click Run.

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REFERENCES

For more information about how to use the sample code in this article, click the article number below to view the article in the Microsoft Knowledge Base:

212536 (http://support.microsoft.com/kb/212536/EN-US/ ) OFF2000: How to Run Sample Code from Knowledge Base Articles

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