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.