readRDS

R Base 3.6.2

Functions to write a single R object to a file, and to restore it.

Syntax

saveRDS(object, file = "", ascii = FALSE, version = NULL,
        compress = TRUE, refhook = NULL)<p></p><p>readRDS(file, refhook = NULL)</p>

Arguments

Parameter	Description
`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 TRUE or NA, an ASCII representation is written; otherwise (default), a binary one is used. See the comments in the help for save.
`version`	the workspace format version to use. NULL specifies the current default version (3). The only other supported value is 2, the default from R 1.4.0 to R 3.5.0.
`compress`	a logical specifying whether saving to a named file is to use "gzip" compression, or one of "gzip", "bzip2" or "xz" to indicate the type of compression to be used. Ignored if file is a connection.
`refhook`	a hook function for handling reference objects.

Return Value

For readRDS, an R object. For saveRDS, NULL invisibly.

Details

These functions 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. All of these interfaces use the same serialization format, which has been used since R 1.4.0 (but extended from time to time as new object types have been added to R). However, save wri

Examples

Example

# NOT RUN {
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))
# }