Re: [R] small problem with predict

From: Petr Pikal <petr.pikal_at_precheza.cz>
Date: Fri 16 Jul 2004 - 21:39:29 EST

Hi Ann

As I read your code mode closely, I suspect that there could be another variables x1 and x2 somewhere in your search path which led to the error.

With fresh R session without any data this works as expected

dold<-data.frame(x1=rnorm(10),x2=5*rnorm(10)) y<-1:10
predict(lm(y~x1+x2,dold),dn,se.fit=T)

Cheers
Petr

On 16 Jul 2004 at 13:19, Petr Pikal wrote:

> Hi
>
> On 16 Jul 2004 at 12:38, Anne wrote:
>
> > hello to all!
> >
> > I have a small problem wit predict() for lm
> >
> > Let's say I have predictors x1 and x2, response y
> >
> > I want to predict for a new ds say
> > dn<-data.frame(x1=
> > seq(min(x1),max(x1),length=10),x2=rep(median(x2),10))
> >
> > predict(lm(y~x1+x2),dn,se.fit=T)
> >
> >
> > Error message
> > > Error: variables 'x1', 'x2' were specified differently from the
> > > fit
>
> AFAIK predixt require to be fed by dataframe in which the
> variables has the same names as was in lm() call. Either call lm()
> with variables named "x1" and "x2" or build the dataframe "dn" with
> names identical as are names in lm() call
>
> Cheers
> Petr
>
>
> >
> > (I looked in the help and found the example
> >
> > x <- rnorm(15)
> > y <- x + rnorm(15)
> > new <- data.frame(x = seq(-3, 3, 0.5))
> > predict(lm(y ~ x), new, se.fit = TRUE)
> >
> > where is the difference?)
> >
> >
> > Anne
> >
> > ----------------------------------------------------
> > Anne Piotet
> > Tel: +41 79 359 83 32 (mobile)
> > Email: anne.piotet@m-td.com
> > ---------------------------------------------------
> > M-TD Modelling and Technology Development
> > PSE-C
> > CH-1015 Lausanne
> > Switzerland
> > Tel: +41 21 693 83 98
> > Fax: +41 21 646 41 33
> > --------------------------------------------------
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@stat.math.ethz.ch mailing list
> > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide!
> > http://www.R-project.org/posting-guide.html
>
> Petr Pikal
> petr.pikal@precheza.cz
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html

Petr Pikal
petr.pikal@precheza.cz



R-help@stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 16 21:47:30 2004

This archive was generated by hypermail 2.1.8 : Fri 18 Mar 2005 - 02:36:39 EST