**Please Note: **
This article is written for users of the following Microsoft Excel versions: 97, 2000, 2002, and 2003. If you are using a later version (Excel 2007 or later), *this tip may not work for you*. For a version of this tip written specifically for later versions of Excel, click here: Playing with a Full Deck.

How's that for a tip title? The title refers to the fact that you may have a need to populate a range of cells with a series of numbers in random order. For instance, you might want to populate 52 cells with the numbers 1 through 52, in random order. (This would be similar to drawing cards from a shuffled deck, thus the tip title.)

There obviously is no built-in Excel function to provide this capability, so you are left to work with macros. Fortunately, such a macro is not terribly difficult to create. The following macro will do the trick nicely:

Sub FillRand() Dim nums() As Integer Dim maxval As Integer Dim nrows As Integer, ncols As Integer Dim j As Integer, k As Integer Dim Ptr As Integer Randomize Set s = Selection maxval = s.Cells.Count nrows = s.Rows.Count ncols = s.Columns.Count ReDim nums(maxval, 2) 'Fill the initial array For j = 1 To maxval nums(j, 1) = j nums(j, 2) = Int((Rnd * maxval) + 1) Next j 'Sort the array based on the random numbers For j = 1 To maxval - 1 Ptr = j For k = j + 1 To maxval If nums(Ptr, 2) > nums(k, 2) Then Ptr = k Next k If Ptr <> j Then k = nums(Ptr, 1) nums(Ptr, 1) = nums(j, 1) nums(j, 1) = k k = nums(Ptr, 2) nums(Ptr, 2) = nums(j, 2) nums(j, 2) = k End If Next j 'Fill in the cells Ptr = 0 For j = 1 To nrows For k = 1 To ncols Ptr = Ptr + 1 s.Cells(j, k) = nums(Ptr, 1) Next k Next j End Sub

This macro uses a two-dimensional array (nums) to figure out which numbers to use and the order in which they should be used. Near the beginning of the macro the array is filled with a static number (1 through the number of cells) and a random number between 1 and the number of cells. This second number is then used to sort the array. Once the array is stored, it is a simple matter to place the original numbers in the cells.

By the way, the reason a two-dimensional array is used is because the Rnd function that VBA uses to generate random numbers can return duplicate values. Thus, even through the second dimension of the array can have duplicates in it, when the array is finally sorted, the first dimension will not have duplicates.

To use the macro, start by selecting the cells you want to have filled with sequential values in a random order. When you run the macro, that range is filled. For instance, if you select ten cells and then run the macro, then those cells are filled with the numbers 1 through 10, in random order.

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This tip (2280) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: **Playing with a Full Deck**.

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2017-12-13 09:03:11

Willy Vanhaelen

@Rick

Interesting link. It gives a better insight in the working of the macro.

2017-12-10 11:21:47

Rick Rothstein

Ah yes, I had forgotten that. The original routine that I developed the code I posted from was an array randomizer where the values were assumed to already be loaded in the array. Those values could be anything (random or ordered numbers, text or a mixture of both) and not simply numbers in numerical order as this article assumed. My original routine is quite old now... I originally published it in an old newsgroup (the predecessors to modern forums) devoted to VB (the compiled version, not the DotNET version) questions. I know the year because my code was incorporated into a web article back then which has a posting date on it of October 18, 1999...

http://vbnet.mvps.org/code/helpers/randomarray.htm

Randy, the man who maintained the website, used my RandomizeArray subroutine as part of a generalized presentation code of his own.

2017-12-10 07:52:09

Willy Vanhaelen

Allen's macro as well as yours and my variant don't scramble the cells, they simply fill the selection with a random list overwriting it's contents. So you you don't have to fill the list with numbers first, you can as well start with an empty selection.

With Nums=Selection and a two dimensional array you get something new: shuffeling the selection maintaining their contents, whatever it is. This can be very usefull too.

2017-12-09 11:11:51

Rick Rothstein

Why would you want to randomly scramble empty cells? The idea behind my original code (which your modification retains) is to randomly rearrange the values within a selected columnar range of cells filled with values. For example, put the numbers 1 through 52 in cells A1:A52, select the range and run the code. if you think of the range as a deck of 52 cards, run the code and it shuffles them, run the code again and it shuffles them again. Of course, the code can randomly reorder any type of values within a columnar range of any size.

2017-12-09 10:37:38

Willy Vanhaelen

Nums=Selection doesn't work. The selection being empty, It produces also an empty array, Or am I missing something?

2017-12-09 02:57:16

Rick Rothstein

Good idea to use a two-dimensional array instead of my one-dimensional array in order to remove the limitation built into the TRANSPOSE function when called from the Evaluate function. One note on that though, instead of loading up the Num array this way...

Nums = Evaluate("ROW(1:" & Selection.Count & ")")

you can simply do this (since Num is declared as a Variant) and end up with the identical array...

Num = Selection

Not sure if that will make the macro faster or not, but it does simplify the creation of the array.

2017-12-08 11:17:12

Willy Vanhaelen

Further investigation revealed that TRANSPOSE is responsible for that. So I tried to produce the Num array only with ROW and it worked though the array is now two dimensional. I further took UBound(Nums) out of the loop because it doesn't change during the execution of the macro anyway. This makes the code in the loop a little bit simpler. Here is the result:

Sub FillRand()

Dim X As Long, RandIndex As Long, Nums As Variant, Cell As Range

Randomize

Nums = Evaluate("ROW(1:" & Selection.Count & ")")

X = UBound(Nums)

For Each Cell In Selection

RandIndex = Int(X * Rnd + 1)

Cell.Value = Nums(RandIndex, 1)

Nums(RandIndex, 1) = Nums(X, 1)

X = X - 1

Next Cell

End Sub

I did a test in Excel 2007 for a whole column and it took only 16 seconds to process the more than a million cells.

2016-01-10 12:16:18

Greg

Sort both the columns using the 'random' column as the key and you've randomised the order.

As in the example above you could end up with the same random number in the sort key but that does not matter.

2016-01-09 10:43:09

Rick Rothstein

2016-01-09 10:35:06

Rick Rothstein

Sub FillRand()

Dim X As Long, RandIndex As Long, Nums As Variant, Cell As Range

Randomize

Nums = Evaluate("TRANSPOSE(ROW(1:" & Selection.Count & "))")

For Each Cell In Selection

RandIndex = Int((UBound(Nums) - X) * Rnd + 1)

Cell.Value = Nums(RandIndex)

Nums(RandIndex) = Nums(UBound(Nums) - X)

X = X + 1

Next

End Sub

2016-01-09 06:11:10

Rick Rothstein

Sub FillRand()

Dim X As Long, RandIndex As Long

Dim Temp As Variant, Nums As Variant

Dim Cell As Range

Randomize

Nums = Evaluate("TRANSPOSE(ROW(1:" & Selection.Count & "))")

For X = UBound(Nums) To 1 Step -1

RandIndex = Int(X * Rnd + 1)

Temp = Nums(RandIndex)

Nums(RandIndex) = Nums(X)

Nums(X) = Temp

Next

For Each Cell In Selection

X = X + 1

Cell.Value = Nums(X)

Next

End Sub

Also note that the selection does not have to be contiguous so long as the parts that make it up do not overlap in any way.

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