[Rd] For wishlist: sanity checks for subsets in lm, glm (PR#515)
Peter Dalgaard BSA
12 Apr 2000 12:12:59 +0200
> to preserve cond as a logical vector, as documented in the help for
> data.frame. However, it is still very unpleasant behaviour, and no
> warnings were issued. I can't help thinking that some sanity checks on
> the subset argument could have helped me.
> So I suggest that the subset argument should either be
> * A logical vector of the same length as the number of rows in the data
> frame, or
> * A numeric vector of unique integers
> to ensure that we really do get a subset of the data frame. The more
> flexible behaviour of "[.data.frame" really isn't required here.
Might be a good idea. Mind you, Splus 3.4 does exatly the same thing,
and I'm a little worried that the uniqueness assumption might kill
some bootstrapping applications:
glm(y ~ x, data=test.data, subset=sample(seq(along=y),replace=T))
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