Hello Everyone- I'm calculating summary statistics on a dataset (~4000 records, observations are not uniformly distributed) using summaryBy and trying to add a column with the number of observations to the output as well. What occurs to me is to use nrow(), but this doesn't appear to be working
I'm able to replicate the same results with an example from the summaryBy docs: data(dietox) dietox12<- subset(dietox,Time==12) library(doBy) #this one works summaryBy(Weight+Feed~Evit+Cu,data=dietox12,FUN=c(mean,var,length)) #adding nrow doesn't give the number of rows summaryBy(Weight+Feed~Evit+Cu,data=dietox12,FUN=c(mean,var,length,nrow)) There must be a way to do this, but I can't figure it out. I suspect there is another function that would be compatible with summaryBy. Thanks in advance. -Tony [[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.