[R] Odp: Odp: sampling problem - new to R

[Petr PIKAL]

> Hi
> 
> If I understand correctly, use split and sample with lapply. If DF is 
your dataframe
> 
> lapply(split(DF$Tree, DF$Plot), function(x) sample(x,1))
> 
> shall select random tree from each plot. Or you can get it in tabular 
form with sapply.
> 
> Regards
> Petr

Sorry, you shall use resample from sample help page as Prof.Ripley pointed 
if you can have length<=1 plot.

Regards
Petr


> 
> r-help-bounces at stat.math.ethz.ch napsal dne 05.06.2007 16:29:49:
> 
> > 
> > I have a data set of individual trees and the plots that they are in:
> > 
> > Tree      Plot
> > 56749    1
> > 63494    1
> > 87375    1
> > 37494    2
> > 92753    3
> > 34847    3
> > 38747    4 etc...
> > 
> > So each plot is represented once for every individual that occurrs in 
it. 
> > Plots get different numbers of rows because there can be a different 
number
> > of individuals in each plot.
> > 
> > I want to make a data frame that consists of one individual from each 
plot. 
> > I would like to randomly choose one individual from each plot that is
> > present in the data set.  I will have to do this to multiple data sets 
which
> > may contain different plots, and may contain up to 1200 plots, so I 
can't
> > choose the plots by hand.
> > 
> > Please help me with this.  I'm an ecologist and I'm in Panama, with no 
one
> > around who is educated in R.  Whoever solves this problem for me will 
be
> > acknowledged in any resulting publications.
> > 
> > Thanks!
> > -Claire
> > -- 
> > View this message in context: 
http://www.nabble.com/sampling-problem---new-to-
> > R-tf3872130.html#a10970708
> > Sent from the R help mailing list archive at Nabble.com.
> > 
> > ______________________________________________
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> > and provide commented, minimal, self-contained, reproducible code.