Import a Python module — import (original) (raw)
Import the specified Python module, making it available for use from R.
import(module, as = NULL, convert = TRUE, delay_load = FALSE)
import_main(convert = TRUE, delay_load = FALSE)
import_builtins(convert = TRUE, delay_load = FALSE)
import_from_path(module, path = ".", convert = TRUE, delay_load = FALSE)
Arguments
The name of the Python module.
An alias for module name (affects names of R classes). Note that this is an advanced parameter that should generally only be used in package development (since it affects the S3 name of the imported class and can therefore interfere with S3 method dispatching).
Boolean; should Python objects be automatically converted to their R equivalent? If set to FALSE
, you can still manually convert Python objects to R via the [py_to_r()](r-py-conversion.html)
function.
Boolean; delay loading the module until it is first used? When FALSE
, the module will be loaded immediately. See Delay Loadfor advanced usages.
The path from which the module should be imported.
Value
An R object wrapping a Python module. Module attributes can be accessed via the $
operator, or via [py_get_attr()](py%5Fget%5Fattr.html)
.
Python Built-ins
Python's built-in functions (e.g. len()
) can be accessed via Python's built-in module. Because the name of this module has changed between Python 2 and Python 3, we provide the function import_builtins()
to abstract over that name change.
Delay Load
The delay_load
parameter accepts a variety of inputs. If you just need to ensure your module is lazy-loaded (e.g. because you are a package author and want to avoid initializing Python before the user has explicitly requested it), then passing TRUE
is normally the right choice.
You can also provide a named list: "before_load"
, "on_load"
and"on_error"
can be functions , which act as callbacks to be run when the module is later loaded. "environment"
can be a character vector of preferred python environment names to search for and use. For example:
delay_load = list(
# run before the module is loaded
before_load = function() { ... }
# run immediately after the module is loaded
on_load = function() { ... }
# run if an error occurs during module import
on_error = function(error) { ... }
environment = c("r-preferred-venv1", "r-preferred-venv2")
)
Alternatively, if you supply only a single function, that will be treated as an on_load
handler.
Import from Path
import_from_path()
can be used in you need to import a module from an arbitrary filesystem path. This is most commonly used when importing modules bundled with anR package – for example:
path <- system.file("python", package = <package>)
reticulate::import_from_path(<module>, path = path, delay_load = TRUE)
Examples
if (FALSE) { # \dontrun{
main <- import_main()
sys <- import("sys")
} # }