In richierocks/pathological: Path Manipulation Utilities

set.seed(19790801)
knitr::opts_chunk$set(error = FALSE)

Convenient Wrappers for Base-R Functions

There are lots of functions in base-R for working with files and directories. Unfortunately, some of them are a little bit annoying to work with. For example, the function names, and the form in which paths are returned, are inconsistent. For example

tempdir()
R.home()

pathological contains standardized wrappers to these functions. These return absolute, unabbreviated paths. You can choose whether you want back or forward slashes to separate directory levels.

library(pathological)
temp_dir()
r_home()

These wrappers are also vectorized.

r_home(c("home", "bin", "share"), c("", "i386", "zoneinfo"))

There are several wrapper functions available in pathological.

wrapper_data <- data.frame(
  "base/utils" = c("choose.files, file.choose", "choose.dir", "dir.create", "file.create", "file.copy", ".libPaths", "R.home", "Sys.which", "system.file", "tempdir", "tempfile"),
  pathological = c("choose_files", "choose_dir", "copy_dir", "create_dirs", "create_files", "get_libraries", "r_home", "sys_which", "system_file", "temp_dir", "temp_file"),
  stringsAsFactors = FALSE
)
knitr::kable(wrapper_data)

The underlying function for creating the standardized paths is standardize_path, with standardise_path also available for fans of British English.

Getting Parts of Files

There are several functions for getting a parts of a file name , or parts of a path. decompose_path splits a path into the directory name, file name without extension, and file extension. The results are returned as a data frame, and multiple dots in the file extension are correctly dealt with. In the following example, the with_dir function from the withr package is used to temporarily change the working directory, to better demonstrate the dirname column returned by decompose_path.

x <- c("foo.tgz", "bar.tar.gz", "baz")
withr::with_dir(
  temp_dir(),
  decompose_path(x)
)

There are several convenience functions that retrieve build on decompose_path.

• get_extension returns only the file extension.
• strip_extension returns the file name without the extension.
• replace_extension replaces the file extension with a new one.
• recompose_path undoes the effects of decompose_path.

split_path splits file paths into directory components, returning a list of character vectors, or a matrix.

split_path(r_home())
split_path(r_home(), simplify = TRUE)

split_dir is a shortcut for dir + split_path, with defaults to make it easy to View the contents of a directory structure.

split_dir(r_home())

Startup files

On startup, you can customize R's behaviour by running an R Profile script, or setting environment variables in an R Environ script. the ?Startup help page details the convoluted process of how it determines which files to run. To save worrying about the details, pathological has some functions that return the paths to these files. r_profile_site returns the path to the site-level R Profile file. r_profile returns the user-level file. If a suitable file cannot be found, NA is returned.

r_profile_site()
r_profile()

r_environ_site and r_environ are the equivalent functions for site and user-level R Environ files, respectively.

Windows-Specific Functionality

There are a few functions for use with Windows file paths.

• is_windows_drive returns \code{TRUE} wherever the input paths are a letter followed by a colon, and optionally a forward or back slash.
• get_windows_drive returns the drive of the input paths.
• cygwinify_path converts a p[ath to a form that cygwin is happy with.

Other Miscellanea

• rstudio_project_dir returns the directory of the current project.
• parent_dir returns the parent directory of the input.
• os_path returns the operating system PATH environment varaible as a character vector.

richierocks/pathological documentation built on May 27, 2019, 8:47 a.m.