pollution-and-prejudice

Targets Notes

Notes about using the targets R package, focused on a few useful functions and options. For a comprehensive reference, see the {targets} user manual: https://books.ropensci.org/targets/

visualize / validate the pipeline

• view the network: tar_visnetwork()
• see a list of the targets: tar_manifest()
• view a simplified network (without functions): tar_glimpse()

run pipeline / clear results

• run the pipeline: tar_make()
• invalidate a particular target, to force it to re-run (regardless of its actual state): tar_invalidate()
• invalidate all targets to force the entire pipeline to re-run (note that this does not destroy the _targets.R file, just the outputs in the _targets folder): tar_destroy()

inspect outputs

These functions allow you to view or load the output object from any target (e.g., a dataset). Before using any of these functions, make sure to load any packages required to use the given object/dataset (e.g., if the target object being retrieved is geospatial data, load the sf package - otherwise you’ll get an error when you try to use that object):

• read an object/target directly (don’t load as a variable): tar_read()
• load an object/target (as a variable in the global environment): tar_load()

debugging / development

Use workspaces:

• save a particular workspace: tar_option_set(workspaces = c(...))
• save a workspace for any target that has an error: tar_option_set(workspace_on_error = TRUE)
• to load a workspace, call: tar_workspace(workspace_name)
• to see available workspaces, call: tar_workspaces()

build reports / presentations

• Quarto: tarchetypes::tar_quarto()
  • embed target objects (e.g., plots) with targets::tar_read(target_name)
  • may also want to include store = here::here(tar_config_get('store'))) in the targets::tar_read() call - this should allow for manual rendering (i.e. without having to render using tar_make() each time) (might not be the best practice though?)
  • make sure packages needed to render the document are included in the .qmd file itself (and not just called by tar_option_set() in the _targets.R file)
• Rmarkdown: tarchetypes::tar_render()