| tempfile {base} | R Documentation |
tempfile returns a vector of character strings which can be used as
names for temporary files.
tempfile(pattern = "file", tmpdir = tempdir(), fileext = "") tempdir()
pattern |
a non-empty character vector giving the initial part of the name. |
tmpdir |
a non-empty character vector giving the directory name |
fileext |
a non-empty character vector giving the file extension |
The length of the result is the maximum of the lengths of the three arguments; values of shorter arguments are recycled.
The names are very likely to be unique among calls to tempfile
in an R session and across simultaneous R sessions (unless
tmpdir is specified). The filenames are guaranteed not to be
currently in use.
The file name is made by concatenating the path given by
tmpdir, the pattern string, a random string in hex and
a suffix of fileext.
By default, tmpdir will be the directory given by
tempdir(). This will be a subdirectory of the per-session
temporary directory found by the following rule when the R session is
started. The environment variables TMPDIR, TMP and
TEMP are checked in turn and the first found which points to a
writable directory is used:
if none succeeds the value of R_USER (see
Rconsole) is used. If the path to the directory
contains a space in any of the components, the path returned will use
the shortnames version of the path.
Note that setting any of these environment variables in the R session
has no effect on tempdir(): the per-session temporary directory
is created before the interpreter is started.
For tempfile a character vector giving the names of possible
(temporary) files. Note that no files are generated by tempfile.
For tempdir, the path of the per-session temporary directory.
Both will use backslash as the path separator.
R processes forked by functions such as mclapply in
package parallel (or multicore) share a per-session
temporary directory. Further, the ‘guaranteed not to be
currently in use’ applies only at the time of asking, and two
children could ask simultaneously. As from R 2.14.1 this is avoided
by ensuring that tempfile calls in different children try
different names.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
unlink for deleting files.
tempfile(c("ab", "a b c")) # give file name with spaces in!
tempfile("plot", fileext=c(".ps", ".pdf"))
tempdir() # works on all platforms with a platform-dependent result