Check out the zoo package and its three vignettes and ?aggregate.zoo in particular.
Also have a look at the article on dates and times in R News 4/1 and note the chron class which, in fact, accepts inputs in the very form you have. On Fri, Oct 3, 2008 at 7:39 PM, Joe Kaser <[EMAIL PROTECTED]> wrote: > Hi and thanks in advance, > > I am fairly new with R so I hope this problem isn't too amateur. > > I have a vector of count data which correspond to vectors of date (%m/%d/%Y) > and time of day (%H:%M:%S). > I am trying to compute various statistics (e.g. daily max) by lumping the > data together by day. I have been able to utilize tapply() and group the > counts together, but with the method I use I end up losing the corresponding > time of day information. > > This is what I have done so far > > data=*vector of integers > *hours= *"character" vector of times %H:%M:S% * > days= *"character" vector of dates %m/%d/%Y > * > hr.days=paste(days,hours) > hr.dayslt=as.POSIXlt(strptime(hr.days, format="%m/%d/%Y %H:%M:%S")) > > tapply(data,hr.dayslt$yday,max) > > This works to give me the counts I want corresponding to a Julain day, but > it does not tell me which hour corresponds to each daily maximum. Is > tapply() the wrong route? > > Joe > * > > > * > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.
