On 17-10-2013, at 18:48, Tim Umbach <tim.umb...@hufw.de> wrote: > Hi there, > > another beginners question, I'm afraid. Basically i want to selct the > maximum of values, that correspond to different variables. I have a table > of oil production that looks somewhat like this: > > oil <- data.frame( YEAR = c(2011, 2012), > TX = c(20000, 30000), > CA = c(40000, 25000), > AL = c(20000, > 21000), > > ND = c(21000,60000)) > > Now I want to find out, which state produced most oil in a given year. I > tried this: > > attach(oil) > last_year = oil[ c(YEAR == 2012), ] > max(last_year) >
For a single year do year <- which(oil[,"YEAR"]==2011) oil[year,which.max(oil[year,]),drop=FALSE] In the help look at base::[.data.frame Berend > Which works, but it doesnt't give me the corresponding values (i.e. it just > gives me the maximum output, not what state its from). > So I tried this: > > oil[c(oil == max(last_year)),] > and this: > oil[c(last_year == max(last_year)),] > and this: > oil[which.max(last_year),] > and this: > last_year[max(last_year),] > > None of them work, but they don't give error messages either, the output is > just "NA". The problem is, in my eyes, that I'm comparing the values of > different variables with each other. Because if i change the structure of > the dataframe (which I can't do with the real data, at least not with out > doing it by hand with a huge dataset), it looks like this and works > perfectly: > > oil2 <- data.frame ( > names = c('YEAR', 'TX', 'CA', 'AL', 'ND'), > oil_2011 = c(2011, 20000, 40000, 20000, 21000), > oil_2012 = c(2012, 30000, 25000, 21000, 60000) > ) > attach(oil2) > oil2[c(oil_2012 == max(oil_2012)),] > > Any help is much appreciated. > > Thanks, Tim Umbach > > [[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. ______________________________________________ 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.