[R] How to view un-sampled data from a randomly sampled dataset

Bert Gunter gunter.berton at gene.com
Wed Oct 23 21:48:27 CEST 2013


... which raises an interesting point: What if some of the values are
replicated? Does the OP want to have a random sample of everything or
of the unique values?

Cheers,
Bert

On Wed, Oct 23, 2013 at 12:39 PM, Nordlund, Dan (DSHS/RDA)
<NordlDJ at dshs.wa.gov> wrote:
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of erinu
>> Sent: Wednesday, October 23, 2013 11:14 AM
>> To: r-help at r-project.org
>> Subject: [R] How to view un-sampled data from a randomly sampled
>> dataset
>>
>> Hi there-
>>
>> I have a 150 row dataset (data). I create "y" a randomly sampled
>> (without
>> replacement) set number of observations (40):
>>
>> y<-data[sample(1:nrow(data),40,replace=FALSE),]
>>
>> I would like to make a new variable "x" that contains the leftover
>> non-sampled 110 observations.  I am sure there is a fairly easy way to
>> do
>> this.
>>
>> Any help would be greatly appreciated.
>>
>> THANKS!
>>
>>
>
> Perhaps something like
>
> ndx <- sample(1:nrow(data),40,replace=FALSE)
> y <- data[ndx,]
> x <- data[-ndx,]
>
>
> hope this is helpful,
>
> Dan
>
> Daniel J. Nordlund, PhD
> Research and Data Analysis Division
> Services & Enterprise Support Administration
> Washington State Department of Social and Health Services
>
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



-- 

Bert Gunter
Genentech Nonclinical Biostatistics

(650) 467-7374



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