Vista - How to Randomize characters in a string

Thanks. Worked great.

"axtens" wrote:

"RICK" wrote:
Man, do peole like to make this complex!

First of all, if you don't *HAVE* to put the characters into a single
string, don't. Put them into an array. But if they are already in an array,
convert the string to an array. Example:

Randomize ' only do this once per file!

Function ShuffleString( str )
Dim temp, i, r, swap
ReDim temp( Len(str) - 1 )
For i = 0 To UBound(temp)
temp(i) = Mid(str,i+1,1)
Next

For i = 0 To UBound(temp)
r = INT( RND() * Len(str) )
swap = temp(r)
temp(r) = temp(i)
temp(i) = swap
Next

ShuffleString = Join(temp,"")
End Function

foo = ShuffleString( "ALLIGATOR" )

***********

Obviously, if you can create the original string in the array, you can
bypass the copy from string to array.

In microsoft.public.scripting.vbscript message <571A454D-2051-46AF-
9EF1-C7017CD27448@xxxxxx>, Tue, 19 Aug 2008 11:37:00, RICK
<RICK@xxxxxx> posted:
That seems inefficient, though, since apparently (for example) for the
9th number it must keep testing until it finds the right one. For nine
or fewer numbers (starting with 1), however, such inefficiency will not
actually make much difference. OTOH, for more numbers ISTM that the
reject-unwanted will need to be recoded, since, by rejecting both
genuine and spurious duplicates, it will not give a uniformly equi-
probable result (and the inefficiency will increase).

If it is necessary to generate a list of integers in a random order (not
needed for this job) then a simple modification of the efficient shuffle
will give an efficient deal, as shown on the cited site.

--
(c) John Stockton, nr London UK. ?@merlyn.demon.co.uk IE7 FF2 Op9 Sf3
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In microsoft.public.scripting.vbscript message <E80766BD-B20E-4F81-9D51-
8CDB55269928@xxxxxx>, Tue, 19 Aug 2008 17:42:01, Old Pedant
<OldPedant@xxxxxx> posted:only once per program execution.
In that code, for a string of length L, RND is called L times, and
Int(RND*L) has L equally-possible values 0..L-1. Therefore, there are
L*L equi-probable sequences when the code is generated, each generating
some string.

For a string containing L distinct characters, there are factorial(L)
possible orders. For any L > 2, l^2 is not a multiple of factorial(L).
Therefore, if I have read your code correctly, it cannot generate all
possible orders with equal probability. But (assuming RND is perfect)
if the multiplier of RND varies linearly between 1 & L, as in the code I
posted earlier, there are factorial(L) possibilities each generating a
different string; so all desired output strings are possible and equi-
probable.

Donald E Knuth :-
"Random numbers should not be generated with a method chosen at random".
Me : ^ or used

--
(c) John Stockton, nr London, UK. ?@merlyn.demon.co.uk Turnpike v6.05 MIME.
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
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"RICK" <RICK@xxxxxx> wrote in message
newsBB59609-64DA-4748-8B5E-4AD72E9BED58@xxxxxx
Since the characters are already random what purpose is served by shuffling
them about?
So far is seems sufficient just to move the last two characters about.

--
Anthony Jones - MVP ASP/ASP.NET

In microsoft.public.scripting.vbscript message <cd59c3e3-4e47-45a0-8fcb-
6dfdf55df355@xxxxxx>, Wed, 20 Aug 2008 22:00:24,
axtens <Bruce.Axtens@xxxxxx> posted:True, but this is News and not E-mail. When writing, one should
consider also that other people may see the code and use it in
circumstances where such error could matter.

For a discussion of the method, see <http://en.wikipedia.org/wiki/Knuth_
shuffle>.

--
(c) John Stockton, near London. *@merlyn.demon.co.uk/?.?.Stockton@xxxxxx
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
Correct <= 4-line sig. separator as above, a line precisely "-- " (SoRFC1036)
Do not Mail News to me. Before a reply, quote with ">" or "> " (SoRFC1036)

On Aug 22, 5:22*pm, Dr J R Stockton <j...@xxxxxx> wrote:

There's a bug somewhere in the test page ... not necessarily in that
part ...

--
(c) John Stockton, near London, UK. Posting with Google.
Mail: J.R.""""""""@physics.org or (better) via Home Page at
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FAQish topics, acronyms, links, etc.; Date, Delphi, JavaScript, ...

On Aug 22, 7:10*pm, Dr J R Stockton <J.R.Stock...@xxxxxx> wrote:Should be

For K = 1 to L : J = L-K
X = Random(J+1) : T = A(X) : A(X) = A(J) : A(J) = T '' Swap A(X)
A(J)

--
* (c) John Stockton, near London, UK. *Posting with Google.
*Mail: J.R.""""""""@physics.org or (better) via Home Page at
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