Hi, I am trying to find the min of day for each student in each year.
Here is the dataset: date studentid year 1/1/05 6:07 AM 236 20082009 3/27/09 9:45 AM 236 20082009 4/29/09 8:44 AM 236 20082009 3/27/09 11:36 AM 310 20082009 4/1/09 10:43 AM 310 20082009 10/15/09 8:54 AM 310 20092010 10/22/09 8:54 AM 310 20092010 10/28/09 8:06 AM 310 20092010 11/19/09 9:06 AM 310 20092010 10/24/07 9:22 AM 335 20072008 12/13/07 9:26 AM 335 20072008 2/25/09 1:49 PM 335 20082009 3/5/09 2:13 PM 335 20082009 4/15/09 1:53 PM 335 20082009 10/24/07 12:14 PM 126 20072008 11/7/07 12:21 PM 126 20072008 3/19/09 8:45 AM 177 20082009 4/2/09 8:54 AM 177 20082009 4/16/09 9:57 AM 177 20082009 day_min <- aggregate(mydata$date, by=list(mydata$schoolid, mydata$year), FUN=min) However, the result shows the date is in format as: "1193242974" instead of "mm/dd/yy HH:MM AM". Is there anyway that I can show original date in the result? Thanks -- View this message in context: http://r.789695.n4.nabble.com/Using-Aggregate-for-Date-tp3265417p3265417.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
