filePath
Construct the path to a file from components and expands Windows Shortcuts along the pathname from root to leaf
Construct the path to a file from components and expands Windows Shortcuts along the pathname from root to leaf. This function is backward compatible with
file.path
() when argument removeUps=FALSE
and
expandLinks="none"
, except that a (character) NA
is
return if any argument is NA.
This function exists on all platforms, not only Windows systems.
- Keywords
- IO
Usage
## S3 method for class 'default':
filePath(..., fsep=.Platform$file.sep, removeUps=TRUE,
expandLinks=c("none", "any", "local", "relative", "network"), mustExist=FALSE,
verbose=FALSE)
Arguments
- ...
- Arguments to be pasted together to a file path and then be
parsed from the root to the leaf where Windows shortcut files are
recognized and expanded according to argument
which
in each step. - fsep
- the path separator to use.
- removeUps
- If
TRUE
, relative paths, for instance "foo/bar/../" are shortend into "foo/", but also "./" are removed from the final pathname, if possible. - expandLinks
- A
character
string. If"none"
, Windows Shortcut files are ignored. If"local"
, the absolute target on the local file system is used. If"relative"
, th - mustExist
- If
TRUE
and if the target does not exist, the original pathname, that is, argumentpathname
is returned. In all other cases the target is returned. - verbose
- If
TRUE
, extra information is written while reading.
Details
If expandLinks != "none"
, each component, call it parent,
in the absolute path is processed from the left to the right as follows:
1. If a "real" directory of name parent exists, it is followed.
2. Otherwise, if Microsoft Windows Shortcut file with name
parent.lnk exists, it is read. If its local target exists, that
is followed, otherwise its network target is followed.
3. If no valid existing directory was found in (1) or (2), the expanded
this far followed by the rest of the pathname is returned quietly.
4. If all of the absolute path was expanded successfully the expanded
absolute path is returned.
Value
- Returns a
character
string.
On speed
Internal file.exists()
is call while expanding the pathname.
This is used to check if there exists a Windows shortcut file named
'foo.lnk' in 'path/foo/bar'. If it does, 'foo.lnk' has to be followed,
and in other cases 'foo' is ordinary directory.
The file.exists()
is unfortunately a bit slow, which is why
this function appears slow if called many times.
See Also
Examples
# Default
print(file.path("foo", "bar", "..", "name")) # "foo/bar/../name"
# Shorten pathname, if possible
print(filePath("foo", "bar", "..", "name")) # "foo/name"
print(filePath("foo/bar/../name")) # "foo/name"
# Recognize Windows Shortcut files along the path, cf. Unix soft links
filename <- system.file("data-ex/HISTORY.LNK", package="R.utils")
print(filename)
filename <- filePath(filename, expandLinks="relative")
print(filename)