Often the purpose of first/last in sas is to facilitate grouping of observations in a sequential algorithm. This purpose is better served in R by using vectorized methods like those in package plyr.
Also, note that first/last has different meanings in the context of "by x;" versus "by x notsorted;". R "duplicated" does not address the latter, which splits noncontiguous records with equal x. Regards, David -- View this message in context: http://r.789695.n4.nabble.com/the-first-from-SAS-in-R-tp3055417p3057476.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.
