Using the zoo package: Lines <- "SST_date SST 2008-01-01 22.2 2008-01-02 21.8 2008-01-03 22.8 2008-01-04 22.9 2008-01-05 23.1 2008-01-06 23.2"
library(zoo) # z <- read.zoo("myfile.dat", header = TRUE) z <- read.zoo(textConnection(Lines), header = TRUE) merge(z, avg3 = rollmean(z, 3, align = "right")) See the three zoo vignettes (pdf documents) for more info on zoo. On Fri, Feb 20, 2009 at 3:38 AM, clion <birt...@hotmail.com> wrote: > > Dear RUsers, > I guess this is an easy question for someone a little familiar with > programming...(which I am not)... > > I've got 2 colummns, one shows just dates(SST_date, Class 'Date' num), the > other one shows the SeaSurfaceTemperature (SST, num) at that certain date. > > SST_date SST > 2008-01-01 22.2 > 2008-01-02 21.8 > 2008-01-03 22.8 > 2008-01-04 22.9 > 2008-01-05 23.1 > 2008-01-06 23.2 > ... > ... > > now, I would like to add a column that shows the mean SST over the last > (e.g.) 60 days (for that specific date). > > My biological question is, whether the birthweight of an animal at a > specific birthdate changes due to the SST over the last 60 days before > birth. (SST is an indicator for food abundance - if food is scarce, mothers > can't feed much and hence, pups are born lighter!?) > Up to now, I can only show, whether the SeaSurfaceTemperatures on the > birthdate can have an influence on birthweight, which is not what I want to > do... > > Can anybody tell me, how to start, where to look it up or help me even more? > thanks in advance. > Birte > > -- > View this message in context: > http://www.nabble.com/mean-over-previous-cells-tp22116807p22116807.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.