How are you using aggregate()? It seems to sum for me... z <- zoo(1:50, seq.POSIXt(from = Sys.time(), by = "30 min", length.out = 50))
aggregate(z, as.Date(time(z)), sum) Best, Michael On Tue, May 15, 2012 at 11:52 AM, Cren <oscar.soppe...@bancaakros.it> wrote: > Hello, > > I have a time series with intraday datas, sampled every 30'; I would need to > aggregate them in this way: summing up all datas within a day. > > I tried to use *aggregate(...)* function to get my goal, but it aggregates > in wrong way (I did not understand how so far); what I need is like > *sum(...)* function applied to datas within the same day. > > Thank you :) > > -- > View this message in context: > http://r.789695.n4.nabble.com/How-to-sum-and-group-data-by-DATE-in-data-frame-tp903708p4630119.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.
