bradleyd wrote > Excuse the request from an R novice! I have a data frame (DATA) that has > two numeric columns (YEAR and DAY) and 4000 rows. For each YEAR I need to > determine the 10% and 90% quantiles of DAY. I'm sure this is easy enough, > but I am a new to this. > >> quantile(DATA$DAY,c(0.1,0.9)) > 10% 90% > 12 29 > > But this is for the entire 4000 rows, when I need it to be for each YEAR. > Is there no way to use a "by" argument in the quantile function? > > Thanks for any help you can provide. > David
check out ?aggregate or ?by should be of help HTH Pete -- View this message in context: http://r.789695.n4.nabble.com/Quantiles-of-a-subset-of-data-tp4659063p4659064.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.