You might want to look into the caTools package: it provides runmean,
runmin, and runmax functions -- if you set those for a window of
length 8 and then take every 8th element, you should get what you're
looking for (much cleaner and faster too!) A good way to do that
subset is something like:
x <- 1:100
y <- x^2 - 3*x + 5
n <- 8
y[!(seq_along(x) %% n)]
Though I'm pretty sure I've seen a cleaner version elsewhere....
Michael
On Fri, Apr 27, 2012 at 11:46 AM, Jonsson <amen.alya...@bordeaux.inra.fr> wrote:
> Hellow everyone,
> This code bellow will calculate average daily wind speed(measurements are
> taken every three hours).Any ideas how to take the Min and Max instead of
> average.
>
> library(Matrix)
> setwd("C:\\Users\\aalyaari\\Desktop\\img")
> listfile<-dir()
> long <- file("C:\\Users\\aalyaari\\Desktop\\New folder (5)\\inra.bin", "rb")
> A=readBin(long, integer(), size=2,n=67420*1, signed=F)
> ta<-t(A)
> lot <- file("C:\\Users\\aalyaari\\Desktop\\New folder (5)\\lat.img", "rb")
> B=readBin(lot, integer(), size=2,n=67420*1, signed=F)
> tb<-t(B)
>
> for (n in 1:length(listfile))
> {
>
> #h[n]=listfile[n]
> h=listfile[n]
> #b[n]=file.info(h[n])$size/67420/4
> b=file.info(h[n])$size/67420/4
>
> wind <- file(h, "rb")
> C=readBin(wind, double(), size=4,n=67420*b, signed=TRUE)
>
> D<-matrix(C,nrow=b,ncol=67420)
>
> for(d in 1:b)
> {
> M <- Matrix(-9999, 360, 720)
> tm<-t(M)
> for(i in 1:67420)
> {
> tm[ta[i],tb[i]]= round(10 * ((D[(d-1)*8+1,i] +
> D[(d-1)*8+2,i]
> +D[(d-1)*8+3,i] +D[(d-1)*8+4,i] +D[(d-1)*8+5,i] +D[(d-1)*8+6,i]
> +D[(d-1)*8+7,i] +D[(d-1)*8+8,i] ) / 8))
>
> }
> to.write <- sprintf("C:\\Users\\aalyaari\\Desktop\\New folder
> (6)\\Yar_%00d.bin", d)
> writeBin(as.integer(tm@x), size=2,to.write)
> }
> }
>
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Min-Max-tp4593065p4593065.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
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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.
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