On 10/08/2020 1:42 p.m., John Mount wrote:
I wish I had started with "I am disappointed that lm() doesn't continue its search for weights
into the calling environment" or "the fact that lm() looks only in the formula
environment and data frame for weights doesn't seem consistent with how other values are
treated."
Normally searching is done automatically by following a chain of
environments. It's easy to add something to the head of the chain (e.g.
data), it's hard to add something in the middle or at the end (because
the chain ends with emptyenv(), which is not allowed to have a parent).
So I'd suggest using
environment(f) <- environment()
before calling lm() if you want the calling environment to be in the
search. Setting it to baseenv() doesn't really make sense, unless you
want to disable all searches except in data, in which case emptyenv()
would make more sense (but I haven't tried it, so it might break something).
Duncan Murdoch
But I did not. So I do apologize for both that and for negative tone on my part.
Simplified example:
d <- data.frame(x = 1:3, y = c(1, 2, 1))
w <- c(1, 10, 1)
f <- as.formula(y ~ x)
lm(f, data = d, weights = w) # works
# fails
environment(f) <- baseenv()
lm(f, data = d, weights = w)
# Error in eval(extras, data, env) : object 'w' not found
On Aug 9, 2020, at 11:56 AM, Duncan Murdoch <murdoch.dun...@gmail.com> wrote:
This is fairly clearly documented in ?lm:
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