Hi, I am trying to aggregate max a Date type column but have weird result, how do I fix this?
> a <- rbind( + data.frame(name='Tom', payday=as.Date('1999-01-01')), + data.frame(name='Tom', payday=as.Date('2000-01-01')), + data.frame(name='Pete', payday=as.Date('1998-01-01')), + data.frame(name='Pete', payday=as.Date('1999-01-01')) + ) > a name payday 1 Tom 1999-01-01 2 Tom 2000-01-01 3 Pete 1998-01-01 4 Pete 1999-01-01 > aggregate(a$payday, list(a$name), max) Group.1 x 1 Tom 10957 2 Pete 10592 Thanks, Richard [[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.