| readRDS | R Documentation |
Functions to write a single R object to a file, and to restore it.
saveRDS(object, file = "", ascii = FALSE, version = NULL,
compress = TRUE, refhook = NULL)
readRDS(file, refhook = NULL)
infoRDS(file)
object |
R object to serialize. |
file |
a connection or the name of the file where the R object is saved to or read from. |
ascii |
a logical. If |
version |
the workspace format version to use. |
compress |
a logical specifying whether saving to a named file is
to use |
refhook |
a hook function for handling reference objects. |
saveRDS and readRDS provide the means to save a single R
object to a connection (typically a file) and to restore the object, quite
possibly under a different name. This differs from save and
load, which save and restore one or more named objects into
an environment. They are widely used by R itself, for example to store
metadata for a package and to store the help.search
databases: the ".rds" file extension is most often used.
Functions serialize and unserialize
provide a slightly lower-level interface to serialization: objects
serialized to a connection by serialize can be read back by
readRDS and conversely.
Function infoRDS retrieves meta-data about serialization produced
by saveRDS or serialize. infoRDS cannot be used to
detect whether a file is a serialization nor whether it is valid.
All of these interfaces use the same serialization format, but save
writes a single line header (typically "RDXs\n") before the
serialization of a single object (a pairlist of all the objects to be
saved).
If file is a file name, it is opened by gzfile
except for save(compress = FALSE) which uses
file. Only for the exception are marked encodings of
file which cannot be translated to the native encoding handled
on Windows.
Compression is handled by the connection opened when file is a
file name, so is only possible when file is a connection if
handled by the connection. So e.g. url
connections will need to be wrapped in a call to gzcon.
If a connection is supplied it will be opened (in binary mode) for the
duration of the function if not already open: if it is already open it
must be in binary mode for saveRDS(ascii = FALSE) or to read
non-ASCII saves.
For readRDS, an R object.
For saveRDS, NULL invisibly.
For infoRDS, an R list with elements version (version
number, currently 2 or 3), writer_version (version of R that
produced the serialization), min_reader_version (minimum version of
R that can read the serialization), format (data representation)
and native_encoding (native encoding of the session that produced
the serialization, available since version 3). The data representation is
given as "xdr" for big-endian binary representation, "ascii"
for ASCII representation (produced via ascii = TRUE or ascii
= NA) or "binary" (binary representation with native
‘endianness’ which can be produced by serialize).
Files produced by saveRDS (or serialize to a file
connection) are not suitable as an interchange format between
machines, for example to download from a website. The
files produced by save have a header identifying the
file type and so are better protected against erroneous use.
serialize, save and load.
The ‘R Internals’ manual for details of the format used.
fil <- tempfile("women", fileext = ".rds")
## save a single object to file
saveRDS(women, fil)
## restore it under a different name
women2 <- readRDS(fil)
identical(women, women2)
## or examine the object via a connection, which will be opened as needed.
con <- gzfile(fil)
readRDS(con)
close(con)
## Less convenient ways to restore the object
## which demonstrate compatibility with unserialize()
con <- gzfile(fil, "rb")
identical(unserialize(con), women)
close(con)
con <- gzfile(fil, "rb")
wm <- readBin(con, "raw", n = 1e4) # size is a guess
close(con)
identical(unserialize(wm), women)
## Format compatibility with serialize():
fil2 <- tempfile("women")
con <- file(fil2, "w")
serialize(women, con) # ASCII, uncompressed
close(con)
identical(women, readRDS(fil2))
fil3 <- tempfile("women")
con <- bzfile(fil3, "w")
serialize(women, con) # binary, bzip2-compressed
close(con)
identical(women, readRDS(fil3))
unlink(c(fil, fil2, fil3))
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.
