Thanks Stephen and Gabor. The zoo package is what I was looking for. On Fri, Oct 3, 2008 at 5:44 PM, Gabor Grothendieck <[EMAIL PROTECTED]>wrote:
> 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. > > > [[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.
