Thank you very much Sarah 2015-04-20 19:05 GMT+02:00 Sarah Goslee <sarah.gos...@gmail.com>:
> On Mon, Apr 20, 2015 at 12:56 PM, Sonia Amin <soniaam...@gmail.com> wrote: > > Sorry Sarah for my basic question: what does "a column was read as > factor" > > mean? > > A factor is one of the basic types of data in R, and in statistics > generally, eg M/F or red/white/blue - a predetermined set of > categories that may or may not have an order. > > More relevantly, if there's something wrong in your data, a stray > letter or quote mark for instance, that column is no longer numeric, > and R will read it as a factor by default, otherwise as character. > > str(data) > > which is NOT the same as just typing data, will show you the classes > of your columns, among other things. > > > When I type data , I obtain all the numeric values and the headears I > added > > (Consommation,Cylindre,Puissance,Poids) > > If you just look at data directly, you'll see what look like numbers, > perhaps, but according to R one or more columns are not actually > numbers. That's why you need str(data). > > Your problem looks like a lack of basic understanding of how R works. > Here are a couple of sources that might help you get started: > http://www.burns-stat.com/documents/tutorials/impatient-r/ > http://cyclismo.org/tutorial/R/ > > > For more help, you should provide at least the output of str(data) to > the list, and ideally a reproducible example. Here are some > suggestions for creating a good reproducible example: > > http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example > > Sarah > > > Thanks > > > > > > > > 2015-04-20 18:40 GMT+02:00 Sarah Goslee <sarah.gos...@gmail.com>: > >> > >> What is the problem? One or more of your columns was read as factor, as > >> > >> str(data) > >> > >> would show you. To avoid this, you can add stringsAsFactors=FALSE to > >> the read.table command, but if you expect your data to be entirely > >> numeric then there's something wrong with it that you need to hunt > >> down. > >> > >> Sarah > >> > >> On Mon, Apr 20, 2015 at 12:33 PM, Sonia Amin <soniaam...@gmail.com> > wrote: > >> > Dear All, > >> > > >> > I have written the following lines: > >> > > >> > > >> > > data<-read.table("C:\\Users\\intel\\Documents\\SIIID\\datamultiplereg.txt",header > >> > = FALSE, sep = "") > >> > colnames(data)<-c("Consommation","Cylindre","Puissance","Poids") > >> > result.model1<-lm(Consommation~Cylindre+Puissance+Poids, data=data) > >> > summary(result.model1) > >> > > >> > I obtained the following message: > >> > > >> > > >> > Call: > >> > lm(formula = Consommation ~ Cylindre + Puissance + Poids, data = data) > >> > > >> > Residuals: > >> > Error in quantile.default(resid) : factors are not allowed > >> > In addition: warning message: > >> > In Ops.factor(r, 2) : > >> > ‘^’ This is not relevant for factors > >> > > >> > > >> > Where is the problem? > >> > Thank you in advance > >> > > >> -- > >> Sarah Goslee > >> http://www.functionaldiversity.org > > > > > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
