[R] cv.glm and "longer object length is not a multiple of shorter object length" error

[Peter Ehlers]

On 2011-07-21 17:29, askantik wrote:
> Hi,
>
> I've done some searching where others have had trouble with this error (or
> "warning" actually), but I'm unable to solve my problem.  I have a data
> sheet with 13 columns and 36 rows.  Each column has exactly the same number
> of rows.  I've created glms and now want to do cross-validation on 2 of
> them.  Please be gentle-- I'm new to R (and statistics, too, for that
> matter).  Any help is greatly appreciated.  Here's my code:
>
> /library(boot)
> n<-length(total_species)
> cv13.err<- cv.glm(nests,glm13)
> cv13.err.5<- cv.glm(nests,glm13,K=5)
> cv18.err<- cv.glm(nests,glm18)
> cv18.err.5<- cv.glm(nests,glm18,K=5)/
>
>
> I get errors starting with the glm18 part.  glm13 is
> *total_species~RH+elev+RH*elev* and glm18 is *total_species~per_cover+RH*
>
> Does it have something to do with the two glms having different numbers of
> parameters?  I'm not sure why it seems okay with what I've done for glm13,
> but not glm18.  Thanks again for any help.
>
> *Warning messages:
> 1: In y - yhat :
>    longer object length is not a multiple of shorter object length*

My guess is that per_cover contains at least one missing value.
You could try

  cv.glm(na.omit(nests), glm18)

I tried glm(..., na.action = na.exclude) but cv.glm() appears not (yet)
to be coded to handle padding of missing values.

Peter Ehlers

>
> --
> View this message in context: http://r.789695.n4.nabble.com/cv-glm-and-longer-object-length-is-not-a-multiple-of-shorter-object-length-error-tp3685622p3685622.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at 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.