I'd like to summarize several variables in a data frame, for multiple groups, and store the results in a data.frame. To do so, I'm using by(). For example:
df<-data.frame(a=1:10,b=11:20,c=21:30,grp1=c("x","y"),grp2=c("x","y"),grp3=c("x","y")) dfsum<-by(df[c("a","b","c")], df[c("grp1","grp2","grp3")], range) The result has a class of "by" and a mode of "list". I'm new to R and can't find any documentation on this class, and don't see methods for it associated with the as.data.frame. How should I go about coercing this to a data frame? Is there a comprehensive source that I'm might be missing, which can tell me such things? Cheers [[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.