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? ______________________________________________ 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.
