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MathGroup Archive 2001

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AW: Rearrangement of a sequence into random order

  • To: mathgroup at smc.vnet.net
  • Subject: [mg28471] AW: [mg28434] Rearrangement of a sequence into random order
  • From: Stefan.Schenderlein at ferring.de
  • Date: Fri, 20 Apr 2001 04:24:19 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Hi Loren,
I think this is exactly what you want. You can find the example in the
HelpBrowser for Built-in Functions. It is the last example on the page.
Stefan

The defined function RandomRelist gives a list with the same members as 
the
input list, but in a random reordering.

RandomRelist[x_List]:=
  Block[{n=x,p},
    =
Do[p=Random[Integer,{1,i}];n[[{p,i}]]=n[[{i,p}]],{i,Length[x]}];n]

In[16]:=
RandomRelist[Range[15]]
Out[16]=
{9,15,8,11,2,10,6,13,12,14,4,3,7,5,1}

> -----Urspr=FCngliche Nachricht-----
> Von:	Loren Dill [SMTP:lorendill at mediaone.net]
> Gesendet am:	Mittwoch, 18. April 2001 09:24
> An:	mathgroup at smc.vnet.net
> Betreff:	[mg28434] Rearrangement of a sequence into random order
>
> Hi,
>
> I'm a math teacher, and need to prepare exams from time to time.  I
> typically prepare questions for the exam in a sequential order 
starting at
> the beginning of the material and going to the end.  I may have 
something
> like 20 short-answer questions.  I want a program that will randomize 
the
> order of the questions.  In other words, I want to provide n, the 
number
> of
> questions, and have the program provide a list of length n that 
contains
> all
> the numbers from 1 to n in a random order without any number being
> repeated
> or omitted.  I'm sure that this is an easy task for Mathematica, but 
I
> can't
> figure out the best way to do it.
>
> Loren Dill
>


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