[R] Problem with col

[Sonia Amin]

Thank you very much Sarah

2015-04-20 19:05 GMT+02:00 Sarah Goslee <sarah.goslee at gmail.com>:

> On Mon, Apr 20, 2015 at 12:56 PM, Sonia Amin <soniaamin5 at 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.goslee at 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 <soniaamin5 at 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
> >
> >
>

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