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. > > ______________________________________________ > 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.