Thanks Arun, this is great. However, it should be just a little bit different:
# id event time time_on_task #1 1 add 1373502892 80 #2 2 add 1373502972 23 #3 3 delete 1373502995 901 #4 4 view 1373503896 100 #5 5 add 1373503996 NA When I calculate difference, I need to know how long each activity was. It is id2-id1 for the first activity... On Thu, Aug 29, 2013 at 11:03 AM, arun <smartpink...@yahoo.com> wrote: > > > 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. > > [[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.
