On Thu, Oct 28, 2010 at 2:02 PM, Jason Kwok <jayk...@gmail.com> wrote: > I was able to get what I wanted using the lag function to offset an addition > period. > > lag(rollapply(xx,3,max),-2) or lag(rollapply(xx,3,max,align="right"),-1) >
Another possibility is to apply the function over the last 4 points including the current point and then throw away the last one before taking the max: > library(zoo) > z <- zoo(101:110) > rollapply(z, 4, function(x) max(x[-4]), align = "right") 4 5 6 7 8 9 10 103 104 105 106 107 108 109 -- Statistics & Software Consulting GKX Group, GKX Associates Inc. tel: 1-877-GKX-GROUP email: ggrothendieck at gmail.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.
