Okay everyone heres a likely softball for someone. Consider the following data frame:
#Create data x<-rep(c(1,15),10) y<-rnorm(20) z<-c(rep("auto",10),rep("bus",10)) a<-rep(c(1,1,2,2,3,3,4,4,5,5),2) #Create Data frame Df<-data.frame(Source=x,Rate=y,Bin=a,Type=z) I want to create a new column the equals the sum of the Rates for each type (1,15) by Bin. A related question: I have been using R for a while now and usually manipulate my data in data frames but i know lists are better for R so perhaps the above should be done using lists. Feel free to offer suggestions coming from that angle. Thanks guys JR- -- View this message in context: http://r.789695.n4.nabble.com/Summarize-by-two-or-more-attributes-tp3529825p3529825.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.