Determine required packages for a model

req_pkgs(x, ...)

# S3 method for model_spec
req_pkgs(x, ...)

# S3 method for model_fit
req_pkgs(x, ...)

Arguments

x	A model specification or fit.
...	Not used.

Value

A character string of package names (if any).

Details

For a model specification, the engine must be set.

The list does not include the parsnip package.

Examples

should_fail <- try(req_pkgs(linear_reg()), silent = TRUE)
should_fail
#> [1] "Error : Please set an engine.\n"
#> attr(,"class")
#> [1] "try-error"
#> attr(,"condition")
#> <error/rlang_error>
#> Please set an engine.
#> Backtrace:
#>   1. pkgdown::deploy_to_branch(new_process = FALSE)
#>   2. pkgdown::build_site(...)
#>   3. pkgdown:::build_site_local(...)
#>   4. pkgdown::build_reference(...)
#>   5. purrr::map(...)
#>   6. pkgdown:::.f(.x[[i]], ...)
#>   7. pkgdown:::data_reference_topic(...)
#>   8. pkgdown:::run_examples(...)
#>   9. pkgdown:::highlight_examples(code, topic, env = env)
#>  10. evaluate::evaluate(x, child_env(env), new_device = TRUE)
#>  11. evaluate:::evaluate_call(...)
#>  21. [ base::eval(...) ] with 1 more call
#>  29. parsnip:::req_pkgs.model_spec(linear_reg())

linear_reg() %>%
  set_engine("glmnet") %>%
  req_pkgs()
#> [1] "glmnet"

linear_reg() %>%
  set_engine("lm") %>%
  fit(mpg ~ ., data = mtcars) %>%
  req_pkgs()
#> [1] "stats"