do 'str(myx)' and you will probably see that 'x2' is a factor even though it appears to be numeric when you print it. To convert it to numeric, you can do:
myx$x2 <- as.numeric(as.character(myx$x2)) On Thu, Oct 23, 2008 at 8:52 PM, Srinivas Iyyer <[EMAIL PROTECTED]> wrote: > Hi Jim, > thank you for tip. However, why it works for you and the same line fails in > my R. > >> myx <-x >> myx > x1 x2 > 1 a 4 > 2 b 3 > 3 c 2 > 4 a 1 > 5 c 2 > 6 f 3 > 7 g 4 > 8 f 5 >> aggregate(x=myx$x2,by =list(myx$x1),max) > Error in Summary.factor(c(4L, 1L), na.rm = FALSE) : > max not meaningful for factors > > Thank you. > > > --- On Thu, 10/23/08, jim holtman <[EMAIL PROTECTED]> wrote: > >> From: jim holtman <[EMAIL PROTECTED]> >> Subject: Re: [R] finding unique and max value from a data.frame >> To: [EMAIL PROTECTED] >> Cc: [EMAIL PROTECTED] >> Date: Thursday, October 23, 2008, 8:41 PM >> ?aggregate >> >> x1 x2 >> 1 a 4 >> 2 b 3 >> 3 c 2 >> 4 a 1 >> 5 c 2 >> 6 f 3 >> 7 g 4 >> 8 f 5 >> > aggregate(x$x2, list(x$x1), max) >> Group.1 x >> 1 a 4 >> 2 b 3 >> 3 c 2 >> 4 f 5 >> 5 g 4 >> > >> >> >> On Thu, Oct 23, 2008 at 8:30 PM, Srinivas Iyyer >> <[EMAIL PROTECTED]> wrote: >> > Hi group, >> > >> > How can I identify an element with max value among >> duplicated elements all in a data frame >> > >> > Example: >> > >> >> x1 >> > x1 x2 >> > 1 a 4 >> > 2 b 3 >> > 3 c 2 >> > 4 a 1 >> > 5 c 2 >> > 6 f 3 >> > 7 g 4 >> > 8 f 5 >> > >> > >> > I want to be able to get a data frame with all >> unique(x1) with max value >> > >> > x1 x2 >> > 1 a 4 >> > 2 b 3 >> > 3 c 2 >> > 5 c 2 >> > 7 g 4 >> > 8 f 5 >> > >> > >> > Could I get some help please. >> > thanks >> > srini >> > >> > ______________________________________________ >> > 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? > > > > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.
