Hi, May be this helps: dat1<- read.table(text=" id user action 1 12 login 2 12 view 3 12 view 4 12 view 5 12 login 6 12 view 7 12 view 8 12 login ",sep="",header=TRUE,stringsAsFactors=FALSE)
split(dat1,cumsum(dat1$action=="login")) #$`1` # id user action #1 1 12 login #2 2 12 view #3 3 12 view #4 4 12 view # #$`2` # id user action #5 5 12 login #6 6 12 view #7 7 12 view # #$`3` # id user action #8 8 12 login A.K. ----- Original Message ----- From: srecko joksimovic <sreckojoksimo...@gmail.com> To: R-help@r-project.org Cc: Sent: Tuesday, August 27, 2013 3:29 PM Subject: [R] Iterate over rows and update values based on condition Hi, I have a data set with structure similar to this: id user action 1 12 login 2 12 view 3 12 view 4 12 view 5 12 login 6 12 view 7 12 view 8 12 login I want to create a list of sessions. That means to split table on every occurrence of "login". Using Java (or some other language), I would probably iterate through rows and create new List instance on every "login", but I guess there is more efficient way to do that using R? Thanks [[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.
