path.expand
Expand ~ in File Paths
Description
Expands a file path by replacing a leading tilde, "~", with the
user's home directory. On UNIX systems, a leading "~user" is
replaced by that user's home directory in the file path.
Usage
path.expand(path)
Arguments
| path |
a character vector giving one or more path names.
|
Details
On Windows, the leading tilde "~" is replaced with the environment
variable
R_USER.
- If R_USER is not given or its length is greater than PATH_MAX (260),
then the environment variable HOME is used.
- If HOME is also not given or its length is greater than PATH_MAX,
then the environment variables HOMEDRIVE and HOMEPATH
are combined to determine the value of "~".
On UNIX systems, "~" is replaced with the value of
the environment variable
HOME.
On UNIX systems, the string "~user" at the beginning of a
path string is replaced with the
home directory of "user" if there is a user of that name.
Value
returns a character vector containing one string for each string
in path. These file paths are expanded if "~" (or "~user"
on UNIX) is at the beginning of a file path string.
Differences between TIBCO Enterprise Runtime for R and Open-source R
In open-source R, path.expand() appears to save the value used for "~" the first time it is called.
Even if the environment variables R_USER, and so on, are changed, further calls to path.expand do not use these environment variables
to determine the value for "~".
In contrast, TIBCO Enterprise Runtime for R reads the current values for R_USER, and so on, whenever path.expand is called.
See Also
Examples
# The ~ is expanded to the user's home directory
path.expand("~/foo")
# on unix, ~bill is expanded to the home directory of user 'bill'
path.expand("~bill/foo")
# List all files in user's home directory
list.files(path.expand("~"))