Note: I am almost certain that this has been asked and answered here
before, so my apologies for the redundant query.
I also know that there are several packages that will do this, but I wish
to do it using base R functions only (see below).
The query: Suppose I have a character vector of names like this:
somenames <- c("Heigh", "Ho", "Silver", "Away")
(maybe dozens or hundreds: i.e. lots of names)
Now suppose want to put these in a model formula like this:
~ (Heigh + Ho + Silver + Away)^2
... But **without** pasting them into a character vector and using
parse(text = ...) , which, I grant, is sometimes the simplest way.
Instead, I want to do it using Base R's computing on the language
functions. I can do this with bquote() or substitute(), for example, like
this:
somenames <- c("Heigh", "Ho", "Silver", "Away")
nms <- lapply(somenames, as.name)
form <- nms[[1]]
for(x in nms[-1])
form <<- bquote(.(form) + .(x), list(form = form, x = x))
## or form <<- substitute(form + x, list(form = form, x = x))
form <- bquote(~ (.(form))^2, list(form =form))
## yielding
> form
~(Heigh + Ho + Silver + Away)^2
My question: Is there a simpler/slicker way to do this? This seems kinda
kludgy, and I have the feeling that I'm missing something obviously better
(in base R only; obviously better stuff is in various packages)
Best to all,
Bert
"An educated person is one who can entertain new ideas, entertain others,
and entertain herself."
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