Generate 3 Unique Random numbers in Microsoft Excel

If you want to generate a list of unique random numbers then you can use RANDBETWEEN functions & VBA RND. In this article, we will generate 3 unique numbers from the provided list.

You can find original question here

Question: I want a macro to generate list of 3 random numbers from a list of numbers saved in column A. There is a condition that VBA code needs to be taken care of. The condition is there are 3 numbers that exist in column B, hence macro needs to create a list of numbers that have not occurred once in column B. In this way, we can have a list of unique numbers in column B & C.

Following is the snapshot of example that we have:

To get the list of unique random numbers; we need to follow the below steps to launch VB editor

Click on Developer tab
From Code group select Visual Basic

Copy the below code in the standard module

Sub RandomNumbers()
    Dim ws As Worksheet
    Dim ar As Variant
    Dim RandomNum As Long
    Dim i As Integer
    Dim myVal As Long
    Randomize
    Set ws = ThisWorkbook.Sheets("Numbers")
    With ws
    ar = .Range("A" & Rows.Count).End(xlUp).Row
    .Range("C1:C3").ClearContents
        For i = 1 To 3
        Do
            RandomNum = Int((1 - ar + 1) * Rnd + ar)
            myVal = .Range("A" & RandomNum).Value
        Loop Until Range("B1:C24").Find(what:=myVal, lookat:=xlWhole) Is Nothing
        .Range("C" & i).Value = myVal
        Next i
    End With
End Sub

To run the macro, we can press F5 key from keyboard if you are active in Visual Basic Editor’s screen
Another way to run the macro is using “ALT + F8” key; select the macro & click on Run button

As we run the VBA code, the unique list of numbers will be automatically generated

Code Explanation:

In the above code, we will use RND & INT function along with For loop & Do loop to get the result.

We declare Dim ws as Worksheet; the purpose of declaring ws as Worksheet is we only want the code to run on a specific worksheet i.e. Numbers in our example
Dim RandomNum As Long: this will save the unique numbers
Set ws = ThisWorkbook.Sheets("Numbers"): this line will ensure that the code runs on Numbers sheet only
The next line of code will use With statement
ar = .Range("A" & Rows.Count).End(xlUp).Row: this line will save the last cell in column A (24 in our example)
.Range("C1:C3").ClearContents: this line will erase any existing content in range C1:C3
Next, we will run For loop starting from 1 to 3 times with Do Loop to generate list of random numbers & checking no duplicates in existing range i.e. column B

Conclusion: We can generate list of distinct random numbers from a list in Microsoft excel with small tweaking in the above VBA code.

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