The function convert an absolute path to a relative path in respect to a reference. The longest common parent directory is taken as reference. Symbolic links are converted to original paths before performing the operation.

abs2rel(path, ref_path, mustWork = NA)

Arguments

path

The path to be converted (if it is not absolute, the current working directory is considered as its parent, and a warning is shown).

ref_path

The reference path to be compared to path to obtain the relative directory. Important: the path is considered as a directory also if it is the path of a file!

mustWork

(optional) logical: if TRUE an error is given if path or ref_path do not exists; if NA (default) then a warning; if FALSE nothing is shown.

Value

The relative path

Note

License: GPL 3.0

References

L. Ranghetti, M. Boschetti, F. Nutini, L. Busetto (2020). "sen2r": An R toolbox for automatically downloading and preprocessing Sentinel-2 satellite data. Computers & Geosciences, 139, 104473. doi: 10.1016/j.cageo.2020.104473 , URL: https://sen2r.ranghetti.info/.

Author

Luigi Ranghetti, phD (2017) luigi.ranghetti@gmail.com

Examples

# the reference path (ref_path <- system.file(package="sf"))
#> [1] "C:/Users/lranghetti/Documents/R/win-library/4.1/sf"
# a path with a common parent with ref_path (in_path_1 <- system.file(package="rgdal"))
#> [1] "C:/Users/lranghetti/Documents/R/win-library/4.1/rgdal"
# a path included in ref_path (in_path_2 <- system.file("DESCRIPTION", package="sf"))
#> [1] "C:/Users/lranghetti/Documents/R/win-library/4.1/sf/DESCRIPTION"
# a path external to ref_path (in Linux) (in_path_3 <- system.file(package="base"))
#> [1] "C:/PROGRA~1/R/R-41~1.0/library/base"
# an unexisting path (in_path_4 <- gsub("sf$","unexistingpackage",ref_path))
#> [1] "C:/Users/lranghetti/Documents/R/win-library/4.1/unexistingpackage"
abs2rel(in_path_1, ref_path)
#> [1] "../rgdal"
abs2rel(in_path_2, ref_path)
#> [1] "./DESCRIPTION"
suppressWarnings(abs2rel(in_path_3, ref_path))
#> [1] "../../../../../../../Program Files/R/R-4.1.0/library/base"
suppressWarnings(abs2rel(in_path_4, ref_path, mustWork=FALSE))
#> [1] "../unexistingpackage"
suppressWarnings(abs2rel(ref_path, ref_path))
#> [1] "."