Hi, Try: dat1<- read.table(text=" id event time 1 add 1373502892 2 add 1373502972 3 delete 1373502995 4 view 1373503896 5 add 1373503996 ",sep="",header=TRUE,stringsAsFactors=FALSE) dat1$time_on_task<- c(NA,diff(dat1$time)) dat1 # id event time time_on_task #1 1 add 1373502892 NA #2 2 add 1373502972 80 #3 3 delete 1373502995 23 #4 4 view 1373503896 901 #5 5 add 1373503996 100
#Not sure whether this depends on the values of "event" or not.. A.K. ----- Original Message ----- From: srecko joksimovic <sreckojoksimo...@gmail.com> To: R help <R-help@r-project.org> Cc: Sent: Thursday, August 29, 2013 1:52 PM Subject: [R] Add new calculated column to data frame Hi, I have a following data set: id event time (in sec) 1 add 1373502892 2 add 1373502972 3 delete 1373502995 4 view 1373503896 5 add 1373503996 ... I'd like to add new column "time on task" which is time elapsed between two events (id2 - id1...). What would be the best approach to do that? Thanks, Srecko [[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. ______________________________________________ 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.
