tar_described_as: Select targets using their descriptions.
In targets: Dynamic Function-Oriented 'Make'-Like Declarative Pipelines

tar_described_as

R Documentation

Select targets using their descriptions.

Description

Select a subset of targets in the ⁠_targets.R⁠ file based on their custom descriptions.

Usage

tar_described_as(
  described_as = NULL,
  tidyselect = TRUE,
  callr_function = callr::r,
  callr_arguments = targets::tar_callr_args_default(callr_function),
  envir = parent.frame(),
  script = targets::tar_config_get("script")
)

Arguments

`described_as`	A `tidyselect` expression to select targets based on their descriptions. For example, `described_as = starts_with("survival model")` matches all targets in the pipeline whose `description` arguments of `tar_target()` start with the text string `"survival model"`.
`tidyselect`	If `TRUE`, return a call to `tidyselect::all_of()` identifying the selected targets, which can then be supplied to any `tidyselect`-compatible names`⁠argument of downstream functions like [tar_make()] and [tar_manifest()]. If⁠`FALSE', return a simple character vector of target names.
`callr_function`	A function from `callr` to start a fresh clean R process to do the work. Set to `NULL` to run in the current session instead of an external process (but restart your R session just before you do in order to clear debris out of the global environment). `callr_function` needs to be `NULL` for interactive debugging, e.g. `tar_option_set(debug = "your_target")`. However, `callr_function` should not be `NULL` for serious reproducible work.
`callr_arguments`	A list of arguments to `callr_function`.
`envir`	An environment, where to run the target R script (default: `⁠_targets.R⁠`) if `callr_function` is `NULL`. Ignored if `callr_function` is anything other than `NULL`. `callr_function` should only be `NULL` for debugging and testing purposes, not for serious runs of a pipeline, etc. The `envir` argument of `tar_make()` and related functions always overrides the current value of `tar_option_get("envir")` in the current R session just before running the target script file, so whenever you need to set an alternative `envir`, you should always set it with `tar_option_set()` from within the target script file. In other words, if you call `tar_option_set(envir = envir1)` in an interactive session and then `tar_make(envir = envir2, callr_function = NULL)`, then `envir2` will be used.
`script`	Character of length 1, path to the target script file. Defaults to `tar_config_get("script")`, which in turn defaults to `⁠_targets.R⁠`. When you set this argument, the value of `tar_config_get("script")` is temporarily changed for the current function call. See `tar_script()`, `tar_config_get()`, and `tar_config_set()` for details about the target script file and how to set it persistently for a project.

Details

Targets with empty descriptions are ignored.

Value

If tidyselect is TRUE, then tar_described_as() returns a call to tidyselect::all_of() which can be supplied to the names argument of functions like tar_manifest() and tar_make(). This allows functions like tar_manifest() and tar_make() to focus on only the targets with the matching descriptions. If tidyselect is FALSE, then tar_described_as() returns a simple character vector of the names of all the targets in the pipeline with matching descriptions.

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) { # for CRAN
tar_dir({ # tar_dir() runs code from a temp dir for CRAN.
tar_script({
  library(targets)
  library(tarchetypes)
  list(
    tar_target(b2, TRUE, description = "blue two"),
    tar_target(b3, TRUE, description = "blue three"),
    tar_target(g2, TRUE, description = "green two"),
    tar_target(g3, TRUE, description = "green three"),
    tar_target(g4, TRUE, description = "green three")
  )
}, ask = FALSE)
tar_described_as(starts_with("green"), tidyselect = FALSE)
tar_make(names = tar_described_as(starts_with("green")))
tar_progress() # Only `g2`, `g3`, and `g4` ran.
})
}

targets documentation built on Oct. 3, 2024, 1:11 a.m.