
Thanks Uwe, 

Your strata suggestion works, thank you, but it has created a dataset of random rows but without the data, other columns involved. You see I would further like to use this random sample for a DFA (lda) analysis. Can you suggest how I would use the strata function to sample a subset of the data.frame?

Thanks
Krystyna 

> Date: Tue, 28 Apr 2009 14:33:22 +0200
> From: ligges@statistik.tu-dortmund.de
> To: kagolabek@hotmail.com
> CC: r-help@r-project.org
> Subject: Re: [R] Random Sample with Unique function
> 
> In order to use stratified sampling, either try to implement it yourself 
> or use the "sampling" package and its function strata() as in:
> 
> s1 <- strata(cc, stratanames="ID", size=rep(1, 20), method="srswr")
> 
> then you will get 1 observation for each ID. Note that it is not 
> important to use "with replacement" in your case, since you only sample 
> 1 obervation for each stratum.
> 
> Uwe Ligges
> 
> 
> 
> 
> Krystyna Golabek wrote:
> > Dear R-users
> > 
> > I have a dataset of 243 lines with replicate information for 20 different individuals (ID). 
> > I would like to randomly sample this dataset 100 times with a selection of unique IDs in each sample.
> > 
> > First to create a random sample I have;
> > 
> > cc<-read.table(blah.blah.blah)
> > names(cc)
> >  [1] "CALL"        "CONTEXT"     "ORDER"       "ID"          "STATUS"     
> > 
> > s1<-cc[sample(1:243,20,replace=TRUE),]
> > 
> > This code samples 20 rows from the dataset but can anyone help me write the code to request unique(ID) in this sample?
> > 
> > Thank you so much for your time and help.
> > 
> > Krystyna Golabek
> > 
> > 
> > 
> > _________________________________________________________________
> > 
> > 
> > 	[[alternative HTML version deleted]]
> > 
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.

_________________________________________________________________


	[[alternative HTML version deleted]]

