R help - Jun 2007 - random numbers selection - simple example

Dear R-help,

Which random number generator function would you recommend for simply picking 15
random numbers from the sequence 0-42? I want to use replacement (so that the 
same number could potentially be picked more than once).

I have read the R-help archives and the statistics and computing book on modern 
Applied statistics with S but the advice seems to be for much form complicated 
examples, there must be a simpler way for what I am trying to do?

If anybody can help me I would greatly appreciate your advice and time,

Best Wishes,

Jenny


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jennifer Barnes
PhD student: long range drought prediction 
Climate Extremes Group
Department of Space and Climate Physics
University College London
Holmbury St Mary 
Dorking, Surrey, RH5 6NT
Web: http://climate.mssl.ucl.ac.uk

Assuming you want only integers, see
?sample

Sarah

On 6/6/07, Jenny Barnes <jmb at mssl.ucl.ac.uk>
wrote:
> Dear R-help,
>
> Which random number generator function would you recommend for simply
picking 15
> random numbers from the sequence 0-42? I want to use replacement (so that
the
> same number could potentially be picked more than once).
>
> I have read the R-help archives and the statistics and computing book on
modern
> Applied statistics with S but the advice seems to be for much form
complicated
> examples, there must be a simpler way for what I am trying to do?
>
> If anybody can help me I would greatly appreciate your advice and time,
>
> Best Wishes,
>
> Jenny
>
>

-- 
Sarah Goslee
http://www.functionaldiversity.org

You're all stars - thanks for the replies - I will go ahead and use 
sample...........
I need to do this about 10,000 times - any suggestions for this or simply put it
in a loop 10,000 times outputting each time to an array?

Best Wishes,

Jenny 

>
>
>  use sample(c(0:42), 15, replace=T)
>
>hope it helps,
>kevin
>
>----- Original Message -----
>From: Jenny Barnes <jmb at mssl.ucl.ac.uk>
>Date: Wednesday, June 6, 2007 10:30 am
>Subject: [R] random numbers selection - simple example
>
>> Dear R-help,
>> 
>> Which random number generator function would you recommend for 
>> simply picking 15 
>> random numbers from the sequence 0-42? I want to use replacement 
>> (so that the 
>> same number could potentially be picked more than once).
>> 
>> I have read the R-help archives and the statistics and computing 
>> book on modern 
>> Applied statistics with S but the advice seems to be for much form 
>> complicated 
>> examples, there must be a simpler way for what I am trying to do?
>> 
>> If anybody can help me I would greatly appreciate your advice and 
>> time,
>> Best Wishes,
>> 
>> Jenny
>> 
>> 
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> Jennifer Barnes
>> PhD student: long range drought prediction 
>> Climate Extremes Group
>> Department of Space and Climate Physics
>> University College London
>> Holmbury St Mary 
>> Dorking, Surrey, RH5 6NT
>> Web: http://climate.mssl.ucl.ac.uk
>> 
>> ______________________________________________
>> R-help at stat.math.ethz.ch mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.htmland provide commented, minimal, self-contained, 
>> reproducible code.
>> 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jennifer Barnes
PhD student: long range drought prediction 
Climate Extremes Group
Department of Space and Climate Physics
University College London
Holmbury St Mary 
Dorking, Surrey, RH5 6NT
Tel: 01483 204149
Mob: 07916 139187
Web: http://climate.mssl.ucl.ac.uk

On 06-Jun-07 14:30:44, Jenny Barnes wrote:
> Dear R-help,
> 
> Which random number generator function would you recommend for
> simply picking 15 random numbers from the sequence 0-42? I want
> to use replacement (so that the same number could potentially be
> picked more than once).
R has the function sample() which samples a given number of items
from a given set, without replacement by default, but with replacement
if you specify this. Enter

  ?sample

for more information. In the above case

  sample((0:42), 15, replace=TRUE)

will do what you seem to describe above. Example:
> sample((0:42), 15, replace=TRUE)
 [1] 26 38  1 41 11 30 22 37 28  0  0 25 10 39 27

if you want them in random order (i.e. "as they come off the line"),
or
> sort(sample((0:42), 15, replace=TRUE))
 [1]  1  3  5  8  8 10 16 17 21 25 30 30 33 34 40

if you want them sorted.

Best wishes,
Ted.
> I have read the R-help archives and the statistics and computing
> book on modern Applied statistics with S but the advice seems to
> be for much form complicated examples, there must be a simpler way
> for what I am trying to do?
> 
> If anybody can help me I would greatly appreciate your advice and time,
> 
> Best Wishes,
> 
> Jenny
--------------------------------------------------------------------
E-Mail: (Ted Harding) <ted.harding at nessie.mcc.ac.uk>
Fax-to-email: +44 (0)870 094 0861
Date: 06-Jun-07                                       Time: 16:24:15
------------------------------ XFMail ------------------------------