dump {base}R Documentation

Text Representations of R Objects

Description

This function takes a vector of names of R objects and produces text representations of the objects on a file or connection. A dump file can usually be sourced into another R (or S) session.

Usage

dump(list, file = "dumpdata.R", append = FALSE, 
     control = "all", envir = parent.frame(), evaluate = TRUE)

Arguments

list character. The names of one or more R objects to be dumped.
file either a character string naming a file or a connection. "" indicates output to the console.
append if TRUE, output will be appended to file; otherwise, it will overwrite the contents of file.
control character vector indicating deparsing options. See .deparseOpts for their description.
envir the environment to search for objects.
evaluate logical. Should promises be evaluated?

Details

At present sourceing may not produce an identical copy of dumped objects. A warning is issued if it is likely that problems will arise, for example when dumping exotic objects such as environments and external pointers.

dump will also warn if fewer characters were written to a file than expected, which may indicate a full or corrupt file system.

A dump file can be sourced into another R (or perhaps S) session, but the function save is designed to be used for transporting R data, and will work with R objects that dump does not handle.

To produce a more readable representation of an object, use control = NULL. This will skip attributes, and will make other simplifications that make source less likely to produce an identical copy. See deparse for details.

To deparse the internal function representation rather than displaying the saved source, use control = c("keepInteger", "quoteExpressions", "showAttributes", "warnIncomplete"). This will lose all formatting and comments, but may be useful in those cases where the saved source is no longer correct.

Promises will normally only be encountered by users as a result of lazy-loading (when the default evaluate = TRUE is essential) and after the use of delayedAssign, when evaluate = FALSE might be intended.

Note

The envir argument was added at version 1.7.0, and changed the default search path for named objects to include the environment from which dump was called.

As dump is defined in the base namespace, the base package will be searched before the global environment unless dump is called from the top level or the envir argument is given explicitly.

To avoid the risk of a source attribute out of sync with the actual function definition, the source attribute of a function will never be dumped as an attribute.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

dput, dget, write.
save for a more reliable way to save R objects.

Examples

x <- 1; y <- 1:10
dump(ls(patt='^[xyz]'), "xyz.Rdmped")
unlink("xyz.Rdmped")

[Package base version 2.1.0 Index]