R: Text Representations of R Objects

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 `source`d 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` and `file` is a character string, 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

If some of the objects named do not exist (in scope), they are omitted, with a warning. If `file` is a file and no objects exist then no file is created.

`source`ing may not produce an identical copy of `dump`ed objects. A warning is issued if it is likely that problems will arise, for example when dumping exotic or complex objects (see the Note).

`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 `source`d 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 representation of a function rather than displaying the saved source, use `control = c("keepInteger", "warnIncomplete", "keepNA")`. 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.

### Value

An invisible character vector containing the names of the objects which were dumped.

### Note

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 prompt or the `envir` argument is given explicitly.

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

Currently environments, external pointers, weak references and objects of type `S4` are not deparsed in a way that can be `source`d. In addition, language objects are deparsed in a simple way whatever the value of `control`, and this includes not dumping their attributes (which will result in a warning).

### 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(pattern = '^[xyz]'), "xyz.Rdmped")
    print(.Last.value)
    unlink("xyz.Rdmped")

[Package base version 3.1.2 Index]