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Creates a Nix expression that reads in a file (or folder of data) using R.

Source: R/rxp_io.R
rxp_r_file.Rd

Creates a Nix expression that reads in a file (or folder of data) using R.

Usage

rxp_r_file(...)

Arguments

...

Arguments passed on to rxp_file

name

Symbol, the name of the derivation.

path

Character, the file path to include (e.g., "data/mtcars.shp") or a folder path (e.g., "data"). See details.

read_function

Function, an R function to read the data, taking one argument (the path). This can be a user-defined function that is made available using user_functions. See details.

user_functions

Character vector, user-defined functions to include. This should be a script (or scripts) containing user-defined functions to include during the build process for this derivation. It is recommended to use one script per function, and only include the required script(s) in the derivation.

nix_env

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

env_var

List, defaults to NULL. A named list of environment variables to set before running the R script, e.g., c(VAR = "hello"). Each entry will be added as an export statement in the build phase.

encoder

Function/character, defaults to NULL. A language-specific serializer to write the loaded object to disk.

  • R: function/symbol/character (e.g., qs::qsave) taking (object, path). Defaults to saveRDS.

  • Python: character name of a function taking (object, path). Defaults to using pickle.dump.

  • Julia: character name of a function taking (object, path). Defaults to using Serialization.serialize.

Value

An object of class rxp_derivation.

Details

The basic usage is to provide a path to a file, and the function to read it. For example: rxp_r_file(mtcars, path = "data/mtcars.csv", read_function = read.csv). It is also possible instead to point to a folder that contains many files that should all be read at once, for example: rxp_r_file(many_csvs, path = "data", read_function = \(x)(readr::read_csv(list.files(x, full.names = TRUE, pattern = ".csv$")))). See the vignette("importing-data") vignette for more detailed examples.

See also

Other derivations: rxp_jl(), rxp_jl_file(), rxp_py(), rxp_py_file(), rxp_qmd(), rxp_r(), rxp_rmd()