[R] Random Sample with Unique function

[Uwe Ligges]

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
> 
> 
> 
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