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Create a Nix expression running a Python function

Source: R/derivs.R
rxp_py.Rd

Create a Nix expression running a Python function

Usage

rxp_py(
  name,
  py_expr,
  additional_files = "",
  nix_env = "default.nix",
  serialize_function = NULL,
  unserialize_function = NULL,
  env_var = NULL
)

Arguments

name

Symbol, name of the derivation.

py_expr

Character, Python code to generate the expression.

additional_files

Character vector, additional files to include. Custom functions must go into a script called "functions.py", and additional files that need to be accessible during the build process can be named anything.

nix_env

Character, path to the Nix environment file, default is "default.nix".

serialize_function

Character, defaults to NULL. The name of the Python function used to serialize the object. It must accept two arguments: the object to serialize (first), and the target file path (second). If NULL, the default behavior uses pickle.dump. Define this function in functions.py.

unserialize_function

Character, defaults to NULL. The name of the Python function used to unserialize the object. It must accept one argument: the file path.

env_var

Character vector, defaults to NULL. A named vector of environment variables before running the Python script, e.g., c(PYTHONPATH = "/path/to/modules"). Each entry will be added as an export statement in the build phase.

Value

An object of class derivation which inherits from lists.

Details

At a basic level, rxp_py(mtcars_am, "mtcars.filter(polars.col('am') == 1).to_pandas()") is equivalent to mtcars_am = mtcars.filter(polars.col('am') == 1).to_pandas(). rxp_py() generates the required Nix boilerplate to output a so-called "derivation" in Nix jargon. A Nix derivation is a recipe that defines how to create an output (in this case mtcars_am) including its dependencies, build steps, and output paths.

See also

Other derivations: rxp_jl(), rxp_py_file(), rxp_qmd(), rxp_r(), rxp_r_file(), rxp_rmd()

Examples

if (FALSE) { # \dontrun{
  rxp_py(
    mtcars_pl_am,
    py_expr = "mtcars_pl.filter(polars.col('am') == 1).to_pandas()"
  )

  # Custom serialization
  rxp_py(
    mtcars_pl_am,
    py_expr = "mtcars_pl.filter(polars.col('am') == 1).to_pandas()",
    serialize_function = "serialize_model",
    additional_files = "functions.py")
} # }