On 11/15/05, tom wright <[EMAIL PROTECTED]> wrote: > Sorry to keep posting but I want to do this right and I'm hoping for > some pointers > I now have two time series objects which I need to subtract. > Unfortunatly the two series dont have the same sample rates. > When I try to subtract them > > avgSub<-avg1-avg2 > > The time series object is clever enough to object. > So I guess I need to write a function for subtraction of the time series > objects which will need to interpolate the samples to the same sampling > time (this linear interpolation should be ok here)
Convert it to zoo, perform the calculation and convert it back: library(zoo) z <- na.approx(merge(as.zoo(ts1), as.zoo(ts2))) as.ts(z[,1] - z[,2]) > I would like to make this function the default one to be used when a ts > subtractin is attempted. Unfortunatly I dont really have much idea where > to start with this. If someone could point me in the direction of some > good reading I'll be grateful. Its not a good idea to change the definition of subtraction in ts but you could create a subclass of ts and then define your own subtraction method for that. "-.myts" <- function(x, y) { z <- na.approx(merge(as.zoo(ts1), as.zoo(ts2))) myts <- as.ts(z[,1] - z[,2]) class(myts) <- c("myts", class(myts)) myts } class(ts1) <- c("myts", class(ts1)) class(ts2) <- c("myts", class(ts2)) ts1 - ts2 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html