R help - Nov 2007 - how to randomize a vector

I have a vector whose length is nearly 70 thousand.
I need randomize it for 1000 times .
for randomizing , I mean ,the elements of the vector remain intact while
their order in the vector get changed randomly.
I have written a function which seems to be able to solve short vectors ,
but waste  a lot of time when dealing with the the long vector mentioned
above.
 
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?sample

On Sun, 11 Nov 2007, leffgh wrote:
>
> I have a vector whose length is nearly 70 thousand.
> I need randomize it for 1000 times .
> for randomizing , I mean ,the elements of the vector remain intact while
> their order in the vector get changed randomly.
> I have written a function which seems to be able to solve short vectors ,
> but waste  a lot of time when dealing with the the long vector mentioned
> above.
>
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

Why didn't you do this in R?
> help.search("random sample")
Help files with alias or concept or title matching 'random sample'
using fuzzy matching:



sample(base)            Random Samples and Permutations



Type 'help(FOO, package = PKG)' to inspect entry 'FOO(PKG)
TITLE'.
> 
See ?sample, e.g.
> t1 <- rnorm(70000)
> system.time(t2 <- sample(t1,size=length(t1)))
   user  system elapsed 
   0.01    0.00    0.01 


Best regards

Frede Aakmann T?gersen
Scientist


UNIVERSITY OF AARHUS
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> -----Oprindelig meddelelse-----
> Fra: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] P? vegne af leffgh
> Sendt: 12. november 2007 07:50
> Til: r-help at r-project.org
> Emne: [R] how to randomize a vector
> 
> 
> I have a vector whose length is nearly 70 thousand.
> I need randomize it for 1000 times .
> for randomizing , I mean ,the elements of the vector remain 
> intact while their order in the vector get changed randomly.
> I have written a function which seems to be able to solve 
> short vectors , but waste  a lot of time when dealing with 
> the the long vector mentioned above.
>  
> --
> View this message in context: 
> http://www.nabble.com/how-to-randomize-a-vector-tf4789292.html
> #a13700770
> Sent from the R help mailing list archive at Nabble.com.
> 
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