save(..., list = character(), file = stop("'file' must be specified"), ascii = FALSE, version = NULL, envir = parent.frame(), compress = !ascii, compression_level, eval.promises = TRUE, precheck = TRUE) save.image(file = ".RData", version = NULL, ascii = FALSE, compress = !ascii, safe = TRUE)
- the names of the objects to be saved (as symbols or character strings).
- A character vector containing the names of objects to be saved.
- a (writable binary-mode) connection or the name of the file where the data will be saved (when tilde expansion is done). Must be a file name for
version = 1.
TRUE, an ASCII representation of the data is written. The default value of
FALSEwhich leads to a binary file being written.
- the workspace format version to use.
NULLspecifies the current default format. The version used from R 0.99.0 to R 1.3.1 was version 1. The default format as from R 1.4.0 is version 2.
- environment to search for objects to be saved.
- logical or character string specifying whether saving to a named file is to use compression.
gzipcompression, and (from R 2.10.0) character strings
"xz"specify the type of compression. Ignored when
fileis a connection and for workspace format version 1.
- integer: the level of compression to be used. Defaults to
gzipcompression and to
- logical: should objects which are promises be forced before saving?
- logical: should the existence of the objects be checked before starting to save (and in particular before opening the file/connection)? Does not apply to version 1 saves.
- logical. If
TRUE, a temporary file is used for creating the saved workspace. The temporary file is renamed to
fileif the save succeeds. This preserves an existing workspace
fileif the save fails, but at the cost of using extra disk space during the save.
The names of the objects specified either as symbols (or character strings) in
... or as a character vector in
list are used to look up the objects from environment
envir. By default promises are evaluated, but if
eval.promises = FALSE promises are saved (together with their evaluation environments). (Promises embedded in objects are always saved unevaluated.)
All R platforms use the XDR (bigendian) representation of C ints and doubles in binary save-d files, and these are portable across all R platforms. (ASCII saves used to be useful for moving data between platforms but are now mainly of historical interest. They can be more compact than binary saves where compression is not used, but are almost always slower to both read and write: binary saves compress much better than ASCII ones.)
Default values for the
version arguments can be modified with the
"save.defaults" option (used both by
save.image), see also the ‘Examples’ section. If a
"save.image.defaults" option is set it is used in preference to
"save.defaults" for function
save.image (which allows this to have different defaults).
A connection that is not already open will be opened in mode
Large files can be reduced considerably in size by compression. A particular 46MB dataset was saved as 35MB without compression in 2 seconds, 22MB with
gzip compression in 8 secs, 19MB with
bzip2 compression in 13 secs and 9.4MB with
xz compression in 40 secs. The load times were 1.3, 2.8, 5.5 and 5.7 seconds respectively. These results are indicative, but the relative performances do depend on the actual file and
xz did unusually well here. It is possible to compress later (with
xz) a file saved with
compress = FALSE: the effect is the same as saving with compression. Also, a saved file can be uncompressed and re-compressed under a different compression scheme (and see
resaveRdaFiles for a way to do so from within R).
... arguments only give the names of the objects to be saved: they are searched for in the environment given by the
envir argument, and the actual objects given as arguments need not be those found.
Saved R objects are binary files, even those saved with
ascii = TRUE, so ensure that they are transferred without conversion of end of line markers and of 8-bit characters. The lines are delimited by LF on all platforms.
Although the default version has not changed since R 1.4.0, this does not mean that saved files are necessarily backwards compatible. You will be able to load a saved image into an earlier version of R unless use is made of later additions (for example, raw vectors or external pointers).
The most common reason for failure is lack of write permission in the current directory. For
save.image and for saving at the end of a session this will shown by messages like
Error in gzfile(file, "wb") : unable to open connection In addition: Warning message: In gzfile(file, "wb") : cannot open compressed file '.RDataTmp', probable reason 'Permission denied'
The defaults were changed to use compressed saves for
save in 2.3.0 and for
save.image in 2.4.0. Any recent version of R can read compressed save files, and a compressed file can be uncompressed (by
gzip -d) for use with very old versions of R.
For other interfaces to the underlying serialization format, see
Documentation reproduced from R 2.15.3. License: GPL-2.