在 R 中动态加载来自 package 的数据

Question

I would like to be able to write the below in a form that uses string interpolation.

r[[glue("fic_{data}")]] <- switch(
        data,
        "data" = fic::data,
        "targets" = fic::targets
)

I have tried things like

r[[glue("fic_{data}")]] <- eval(glue("fic::{data}"))
r[[glue("fic_{data}")]] <- eval(sym(glue("fic::{data}")))
r[[glue("fic_{data}")]] <- eval(glue("fic::{!!data}"))

in many combinations and placements of sym and !!.

Is it possible to do and how if so?

Answer 1

With eval , we may need the parse as well

> eval(glue("collapse::wlddev"))
collapse::wlddev

returns just the glue object

> str(eval(parse(text = glue("collapse::wlddev"))))
'data.frame':   13176 obs. of  13 variables:
 $ country: chr  "Afghanistan" "Afghanistan" "Afghanistan" "Afghanistan" ...
  ..- attr(*, "label")= chr "Country Name"
 $ iso3c  : Factor w/ 216 levels "ABW","AFG","AGO",..: 2 2 2 2 2 2 2 2 2 2 ...
  ..- attr(*, "label")= chr "Country Code"
 $ date   : Date, format: "1961-01-01" "1962-01-01" "1963-01-01" "1964-01-01" ...
 $ year   : int  1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 ...
...

Or use the parse_expr from rlang

eval(rlang::parse_expr(glue("collapse::wlddev")))

---

Another option is to pass the string in the data to load the data

data(list = "wlddev", package = "collapse")
head(wlddev)