R: List Objects

ls {base} | R Documentation

## List Objects

### Description

`ls` and `objects` return a vector of character strings giving the names of the objects in the specified environment. When invoked with no argument at the top level prompt, `ls` shows what data sets and functions a user has defined. When invoked with no argument inside a function, `ls` returns the names of the functions local variables. This is useful in conjunction with `browser`.

### Usage

    ls(name, pos = -1, envir = as.environment(pos),
       all.names = FALSE, pattern)
    objects(name, pos= -1, envir = as.environment(pos),
            all.names = FALSE, pattern)

### Arguments

`name` | which environment to use in listing the available objects. Defaults to the current environment. Although called `name` for back compatibility, in fact this argument can specify the environment in any form; see the details section.
`pos` | An alternative argument to `name` for specifying the environment as a position in the search list. Mostly there for back compatibility.
`envir` | an alternative argument to `name` for specifying the environment evaluation environment. Mostly there for back compatibility.
`all.names` | a logical value. If `TRUE`, all object names are returned. If `FALSE`, names which begin with a ``.'' are omitted.
`pattern` | an optional regular expression, see `grep`. Only names matching `pattern` are returned.

### Details

The `name` argument can specify the environment from which object names are taken in one of several forms: as an integer (the position in the `search` list); as the character string name of an element in the search list; or as an explicit `environment` (including using `sys.frame` to access the currently active function calls). By default, the environment of the call to `ls` or `objects` is used. The `pos` and `envir` arguments are an alternative way to specify an environment, but are primarily there for back compatibility.

### See Also

`apropos` (or `find`) for finding objects in the whole search path; `grep` for more details on ``regular expressions''; `class`, `methods`, etc. for object-oriented programming.

### Examples

    .Ob <- 1
    ls(pat="O")
    ls(pat="O", all = TRUE)    # also shows ".[foo]"

    # shows an empty list because inside myfunc no variables are defined
    myfunc <- function() {ls()}
    myfunc()

    # define a local variable inside myfunc
    myfunc <- function() {y <- 1; ls()}
    myfunc()                # shows "y"

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