Hi, Try this example: set.seed(1)
dat2<-data.frame(patient=rep(c(1:20),5),cost=rnorm(100,15,1)) agg1<-aggregate(dat2,by=list(dat2$patient),FUN=sum) agg2<-agg1$cost> 75 agg3<-data.frame(agg1[agg2,2:3]) A.K. ----- Original Message ----- From: mkm1616 <mkm1...@gmail.com> To: r-help@r-project.org Cc: Sent: Tuesday, June 5, 2012 11:34 AM Subject: [R] need descriptive help Hi all, I'm new to using R, and apologize for simplicity of this question. I'm using a data set with over 60,000 observations, Two variables are patient ID, and cost incurred by the patient. I'd like to generate frequency/table by patient and cost IF the total cost is over 2000. Right now I'm using: by(x$cost, x$patient, sum) but this generates a huge list for each patient. What is the best way to either (1) export the output into a csv so I can visually inspect each patient or more helpful (2) create the table IF sum of cost > 1000 Thanks! ______________________________________________ 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. ______________________________________________ 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.