---------- Forwarded message ---------- From: John-Paul Bogers <john-paul.bog...@ua.ac.be> Date: Sat, Jun 26, 2010 at 10:14 PM Subject: Re: [R] Recoding dates to session id in a longitudinal dataset To: jim holtman <jholt...@gmail.com>
Dear Jim, he data concerns HPV screening data. The data looks as follows pat1 sampledate1 HPV16 0.3 pat2 sampledate2 HPV16 0 pat3 sampledata3 HPV16 0.5 pat1 sampledate4 HPV16 0.6 pat4 sampledate5 HPV16 0 pat2 sampledate6 HPV16 0 pat1 sampledate7 HPV16 0 What I would like is pat1 1 HPV16 0.3 pat2 1 HPV16 0 pat3 1 HPV16 0.5 pat1 2 HPV16 0.6 pat4 1 HPV16 0 pat2 2 HPV16 0 pat1 3 HPV16 0 I would like to recode sampledate (real date, in date format) to session sequence (first sample of this patient, second sample of this patient, ....) I hope this makes it clear. Thanks JP PS: I answered this as a reply to your private mail, how do I get this on the mailinglist? On Sat, Jun 26, 2010 at 7:59 PM, jim holtman <jholt...@gmail.com> wrote: > It would be useful if you could provide an example of what the data > looks like now and what you would like it to look like; otherwise it > is impossible to help. > > On Sat, Jun 26, 2010 at 8:37 AM, John-Paul Bogers > <john-paul.bog...@ua.ac.be> wrote: > > Hi, > > > > I'm fairly new to R but I have a large dataset (300000 obs) containing > > patient material. Some patients came 2-9 times during the three year > > observation period. The patients are identified by a unique idnr, the > > sessions can be distinguished using the session date. How can I recode > the > > date of the session to a session id (1-9). This would be necessary to > obtain > > information and do some analysis on the first occurence of a specific > > patient or to look for trends. > > > > Thanks > > > > JP Bogers > > University of Antwerp > > > > [[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. > > > > > > -- > Jim Holtman > Cincinnati, OH > +1 513 646 9390 > > What is the problem that you are trying to solve? > [[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.
