[R] Random sampling based on the observations

[Arup]

Thank you Adrian. Its working.Thank you so much. Take care =^D=)

Cheers

Arup Pramanik
Business Analyst
Redwood Associates
Bangalore,India.



Adrian Dusa wrote:
> 
> On Tuesday 24 March 2009, you wrote:
>> Hello!I am having a problem with Random sampling in R. I have used a
>> syntax: mydata.sub=sample(mydata,7,replace=FALSE,prob=NULL) which allows
>> me
>> to choose a random sample based on the variables(correct me if I am
>> wrong!).
> 
> Actually, no.
> You are sampling from a vector, and where you're using the sampled values
> (on 
> the rows or on the variables) is up to you.
> 
> Let's say we have a dataset with 100 cases and 10 variables:
> 
> Case 1:
> mydata.sub <- mydata[ , sample(10, 7)]
> 
> This will sample 7 variables out of 10.
> 
> Case 2:
> mydata.sub <- mydata[sample(100, 10), ]
> 
> This will sample 10 cases out of 100.
> 
>> Suppose I have 10 variable and if I use the above mentioned
>> command then it will choose 7 variables out of the 10 randomly. My
>> problem
>> is that I want to have a random sample which is not based on the
>> variables
>> but on the values of the variables that is the random sample will be
>> based
>> on the observations. It will be great if someone can help me out me out
>> with
>> a proper syntax. Thanks in Advance.
> 
> I think you need to read the help for:
> ?"["
> 
> and most probably one of the introductory books for R.
> I hope this helps,
> Adrian
> 
> 
> -- 
> Adrian Dusa
> Romanian Social Data Archive
> 1, Schitu Magureanu Bd.
> 050025 Bucharest sector 5
> Romania
> Tel.:+40 21 3126618 \
>      +40 21 3120210 / int.101
> Fax: +40 21 3158391
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at 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.
> 
> 

-- 
View this message in context: http://www.nabble.com/Random-sampling-based-on-the-observations-tp22673975p22681075.html
Sent from the R help mailing list archive at Nabble.com.