Message-ID: <4F4601DE-0AAE-47C8-BD5D-1AF9702FD52D@illinois.edu>
Date: 2020-10-23T15:27:25Z
From: Roger Koenker
Subject: formula mungeing
In-Reply-To: <CAP01uRn3WTMtm+13vMNh8GgX+TASqAtNWmR2wR=QhHC2is-Amg@mail.gmail.com>
Thanks, Gabor! Very elegant!
> On Oct 23, 2020, at 4:15 PM, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
>
> Recursively walk the formula performing the replacement:
>
> g <- function(e, ...) {
> if (length(e) > 1) {
> if (identical(e[[2]], as.name(names(list(...))))) {
> e <- eval(e, list(...))
> }
> if (length(e) > 1) for (i in 1:length(e)) e[[i]] <- Recall(e[[i]], ...)
> }
> e
> }
>
> g(f, lambdas = 2:3)
> ## y ~ qss(x, lambda = 2L) + qss(z, 3L) + s
>
> On Fri, Oct 23, 2020 at 9:33 AM Koenker, Roger W <rkoenker at illinois.edu> wrote:
>>
>> Suppose I have a formula like this:
>>
>> f <- y ~ qss(x, lambda = lambdas[1]) + qss(z, lambdas[2]) + s
>>
>> I?d like a function, g(lambdas, f) that would take g(c(2,3), f) and produce the new
>> formula:
>>
>> y ~ qss(x, lambda = 2) + qss(z, 3) + s
>>
>> For only two qss terms I have been using
>>
>> g <- function(lambdas, f){
>> F <- deparse(f)
>> F <- gsub("lambdas\\[1\\]",lambdas[1],F)
>> F <- gsub("lambdas\\[2\\]",lambdas[2],F)
>> formula(F)
>> }
>> but this is ugly and doesn?t extend nicely to more qss terms. Isn?t there some
>> bquote() magic that can be invoked? Or something else entirely?
>> ______________________________________________
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>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Statistics & Software Consulting
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> email: ggrothendieck at gmail.com