tar_read_raw: Read a target's value from storage (raw version)

In targets: Dynamic Function-Oriented 'Make'-Like Declarative Pipelines

Read a target's value from storage (raw version)

Description

Like tar_read() except name is a character string. Do not use in knitr or R Markdown reports with tarchetypes::tar_knit() or tarchetypes::tar_render().

Usage

tar_read_raw(
  name,
  branches = NULL,
  meta = tar_meta(store = store),
  store = targets::tar_config_get("store")
)

Arguments

name	Character, name of the target to read.
branches	Integer of indices of the branches to load if the target is a pattern.
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.
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

The target's return value from its file in ⁠_targets/objects/⁠, or the paths to the custom files and directories if format = "file" was set.

Storage access

Several functions like tar_make(), tar_read(), tar_load(), tar_meta(), and tar_progress() read or modify the local data store of the pipeline. The local data store is in flux while a pipeline is running, and depending on how distributed computing or cloud computing is set up, not all targets can even reach it. So please do not call these functions from inside a target as part of a running pipeline. The only exception is literate programming target factories in the tarchetypes package such as tar_render() and tar_quarto().

Several functions like tar_make(), tar_read(), tar_load(), tar_meta(), and tar_progress() read or modify the local data store of the pipeline. The local data store is in flux while a pipeline is running, and depending on how distributed computing or cloud computing is set up, not all targets can even reach it. So please do not call these functions from inside a target as part of a running pipeline. The only exception is literate programming target factories in the tarchetypes package such as tar_render() and tar_quarto().

See Also

Other data: tar_crew(), tar_load_everything(), tar_load_raw(), tar_load(), tar_objects(), tar_pid(), tar_process(), tar_read()

Examples

if (identical(Sys.getenv("TAR_EXAMPLES"), "true")) { # for CRAN
tar_dir({ # tar_dir() runs code from a temp dir for CRAN.
tar_script(list(tar_target(x, 1 + 1)), ask = FALSE)
tar_make()
tar_read_raw("x")
})
}

targets documentation built on Oct. 12, 2023, 5:07 p.m.