Select target objects from a target list.
Arguments
- targets
A list of target objects as described in the "Target objects" section. It does not matter how nested the list is as long as the only leaf nodes are targets.
- ...
One or more comma-separated
tidyselect
expressions, e.g.starts_with("prefix")
. Just like...
indplyr::select()
.
Target objects
Most tarchetypes
functions are target factories,
which means they return target objects
or lists of target objects.
Target objects represent skippable steps of the analysis pipeline
as described at https://books.ropensci.org/targets/.
Please read the walkthrough at
https://books.ropensci.org/targets/walkthrough.html
to understand the role of target objects in analysis pipelines.
For developers, https://wlandau.github.io/targetopia/contributing.html#target-factories explains target factories (functions like this one which generate targets) and the design specification at https://books.ropensci.org/targets-design/ details the structure and composition of target objects.
See also
Other target selection:
tar_select_names()
Examples
if (identical(Sys.getenv("TAR_LONG_EXAMPLES"), "true")) {
targets::tar_dir({ # tar_dir() runs code from a temporary directory.
targets <- list(
list(
targets::tar_target(x, 1),
targets::tar_target(y1, 2)
),
targets::tar_target(y2, 3),
targets::tar_target(z, 4)
)
tar_select_targets(targets, starts_with("y"), contains("z"))
})
}