At 10:47 13/09/2007, T.Lok wrote: >Yesterday I spend the whole day struggling on how to get the maximum >value of "y" for every unique value of "x" from the dataframe >"test". In the R Book (Crawley, 2007) an example of this can be >found on page 121. I tried to do it this way, but I failed. > >In the end, I figured out how to get it working (first order, and >afterwards use !duplicated()). My question is: why does it not work >with the unique() function on p. 121 ( >i.e. test[rev(order(x)),][unique(y),]) ?
This is not a direct answer to your question but is not tapply(y, x, max) a simpler way to do what you want? Michael Dewey http://www.aghmed.fsnet.co.uk ______________________________________________ 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.
