targets: tar_load – R documentation

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tar_load

Load the values of targets.

Description

Load the return values of targets into the current environment (or the environment of your choosing). For a typical target, the return value lives in a file in _targets/objects/. For dynamic files (i.e. format = "file") the paths loaded in place of the values.

Usage

tar_load(
  names,
  branches = NULL,
  meta = tar_meta(targets_only = TRUE, store = store),
  strict = TRUE,
  silent = FALSE,
  envir = parent.frame(),
  store = targets::tar_config_get("store")
)

Arguments

`names`	Names of the targets to load. You can supply symbols, a character vector, or `tidyselect` helpers like `all_of()` and `starts_with()`. Names are selected from the metadata in `_targets/meta`, which may include errored targets.
`branches`	Integer of indices of the branches to load for any targets that are patterns.
`meta`	Data frame of metadata from `tar_meta()`. `tar_read()` with the default arguments can be inefficient for large pipelines because all the metadata is stored in a single file. However, if you call `tar_meta()` beforehand and supply it to the `meta` argument, then successive calls to `tar_read()` may run much faster.
`strict`	Logical of length 1, whether to error out if one of the selected targets cannot be loaded. Set to `FALSE` to just load the targets that can be loaded and skip the others.
`silent`	Logical of length 1. If `silent` is `FALSE` and `strict` is `FALSE`, then a message will be printed if a target cannot be loaded, but load failures will not stop other targets from being loaded.
`envir`	Environment to put the loaded targets.
`store`	Character of length 1, path to the `targets` data store. Defaults to `tar_config_get("store")`, which in turn defaults to `_targets/`. When you set this argument, the value of `tar_config_get("store")` is temporarily changed for the current function call. See `tar_config_get()` and `tar_config_set()` for details about how to set the data store path persistently for a project.

Value

Nothing.

Limited scope

tar_read() and tar_load() are only for exploratory analysis and literate programming, and tar_read_raw() and tar_load_raw() are only for exploratory analysis. targets automatically loads the correct dependencies into memory when the pipeline is running, so invoking these functions from inside a target is rarely advisable.

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) {
tar_dir({ # tar_dir() runs code from a temporary directory.
tar_script({
  list(
    tar_target(y1, 1 + 1),
    tar_target(y2, 1 + 1),
    tar_target(z, y1 + y2)
  )
}, ask = FALSE)
tar_make()
tar_load(starts_with("y")) # see also all_of()
})
}

targets

Dynamic Function-Oriented 'Make'-Like Declarative Workflows

v0.10.0

MIT + file LICENSE

Authors

William Michael Landau [aut, cre] (<https://orcid.org/0000-0003-1878-3253>), Matthew T. Warkentin [ctb], Samantha Oliver [rev] (<https://orcid.org/0000-0001-5668-1165>), Tristan Mahr [rev] (<https://orcid.org/0000-0002-8890-5116>), Eli Lilly and Company [cph]

Initial release