Thanks, Phil and Marc; exactly what I needed! I didn't know about the diff function.
--Chris Christopher W. Ryan, MD SUNY Upstate Medical University Clinical Campus at Binghamton 40 Arch Street, Johnson City, NY 13790 cryanatbinghamtondotedu "If you want to build a ship, don't drum up the men to gather wood, divide the work and give orders. Instead, teach them to yearn for the vast and endless sea." [Antoine de St. Exupery] Marc Schwartz wrote: > > On Jul 21, 2009, at 4:58 PM, Christopher W. Ryan wrote: > >> I have a long sequence of dates, about 6 years worth, as one column in a >> data frame. How can I test whether the sequence is consecutive, that is, >> without gaps? >> >> Thanks. >> >> --Chris > > > Chris, > > Presuming that your data frame is called DF, the date column is called > 'date' AND 'date' has been coerced to a Date class, you could use: > > all(diff(DF$date) == 1) > > which will tell you if all of the differences between successive dates > in the column are one day. > > See ?diff for more information. > > If the dates have not yet been coerced to a Date class, see ?as.Date. > > HTH, > > Marc Schwartz > > ______________________________________________ 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.
