[R] Error message from CV.GLM

[Prof Brian Ripley]

Who said the variables were all in the data frame?  See this

      All the variables in 'formula', 'subset' and in '...' are looked
      for first in 'data' and then in the environment of 'formula' (see
      the help for 'formula()' for further details) and collected into a
      data frame.

Now ydata$y is not in the data frame ... so try putting it there.

On Tue, 20 Jan 2009, Markus Mühlbacher wrote:

> Dear list members.
>
> I have problems with the usage of cv.glm from the boot package. Here are some parts of the script I wanted to use:
>
> data <- read.table("selected_2D.csv", header=TRUE, sep=",")
> …
> glm.fitted <- glm("ydata$ y  ~ 1 + density + vsurf_ID6 + vsurf_S ", data=data)
> error <- cv.glm(data=data, glm.fitted, K=6)
>
> ydata$y is a separate data set, where I take my independent data from. I build an equation with some of the columns in data. Then I generate the generalized linear model, which works. But when I try to run the last line – the cv.glm function, I get the following error message:
>
> Error in model.frame.default(formula = eqfull, data = list(vsurf_ID6 = c(2.4599824,  :
>  variable lengths differ (found for 'density')
>
> I fear I don't get the meaning of the error message at all. The length of the data columns are all equal. Any help would be kindly appreciated!
>
> Best wishes,
> Markus
>
>
>
>
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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