Petr PIKAL wrote:
Hi
[EMAIL PROTECTED] napsal dne 10.11.2008 13:25:41:
Hi,
I want to sample a block of information.
Let's say x is a time series. Using sample(x,5) I get a random sample of
length 5 from x.
Is it possible to sample consecutive observations, i.e. I sample one
observation and also get the next 4 observations?
Easy
sam <- sample(x,1)
x[sam:(sam+4)]
You mean
sam <- sample(seq_along(x),1)
x[sam:(sam+4)]
I think this answers the question as posed, but possibly not as meant.
You might have
block <- seq_along(x) %/% 5
and want to an entire block. This is a little more tricky:
bl <- sample(unique(block),1)
x[block==bl]
It gets even trickier if you want to vectorize sampling of multiple
blocks, but let's leave that for now.
Regards
Petr
Thanks a lot!
Martin
--
View this message in context:
http://www.nabble.com/how-to-sample-a-block-
tp20418997p20418997.html
Sent from the R help mailing list archive at Nabble.com.
______________________________________________
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.
______________________________________________
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.
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
______________________________________________
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.
