[Rd] Augment base::replace(x, list, value) to allow list= to be a predicate?

[Gabor Grothendieck]

This could be extended to sub and gsub as well which gsubfn in the
gusbfn package already does:

  library(gsubfn)
  gsubfn("^..", toupper, c("abc", "xyz"))
  ## [1] "ABc" "XYz"

On Fri, Mar 3, 2023 at 7:22 PM Pavel Krivitsky <p.krivitsky using unsw.edu.au> wrote:
>
> Dear All,
>
> Currently, list= in base::replace(x, list, value) has to be an index
> vector. For me, at least, the most common use case is for list= to be
> some simple property of elements of x, e.g.,
>
> x <- c(1,2,NA,3)
> replace(x, is.na(x), 0)
>
> Particularly when using R pipes, which don't allow multiple
> substitutions, it would simplify many of such cases if list= could be a
> function that returns an index, e.g.,
>
> replace <- function (x, list, values, ...) {
>   # Here, list() refers to the argument, not the built-in.
>   if(is.function(list)) list <- list(x, ...)
>   x[list] <- values
>   x
> }
>
> Then, the following is possible:
>
> c(1,2,NA,3) |> replace(is.na, 0)
>
>                         Any thoughts?
>                         Pavel
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