[Rd] weights in lm, glm (PR#9023)

[Peter Dalgaard]

Thomas Lumley <tlumley at u.washington.edu> writes:

> The other approach is to set the environment of the formula to be the 
> current environment. This will work as long as the formula doesn't refer 
> to any variables in its original environment
> 
>     environment(model)<-environment()
>     w<-runif(nrow(data))
>     lm(model,data=data, weights=w)

The cleanest way I can think of is

e <- new.env(parent=environment(model))
assign(".weight.", whatever, envir=e)
environment(model) <- e
lm(model, data=data, weights=.weight.)

(You could assign directly into environment(model), but that might
have side effects. Use a "strange" name so as not to clash with
variables in "data", or in environment(model))

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