Microsoft KB Archive/151470

= How to Create a List of Unique Random Integers Between Two Given Values =

Article ID: 151470

Article Last Modified on 10/11/2006

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APPLIES TO


 * Microsoft Excel 95 Standard Edition
 * Microsoft Excel 5.0 Standard Edition
 * Microsoft Excel 98 for Macintosh

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This article was previously published under Q151470





SUMMARY
In Microsoft Excel, you can write a macro to create a list of unique random integers between two numbers.



MORE INFORMATION
Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers 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 requirements. The following macro prompts the user for a starting integer and an ending integer, then the macro prompts the user to input the number of random numbers to generate. Next, it lists that number of unique integers on the active worksheet. To create and run the macro, follow these steps:   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  Open a blank worksheet. On the Tools menu, click Macro.

In Microsoft Excel 97, on the Tools menu, point to Macro, and click Macros. Click the Unique_Numbers macro, and then click Run.

