R: Find All Names in an Expression

all.names {base} | R Documentation

## Find All Names in an Expression

### Description

Return a character vector containing all the names which occur in an expression or call.

### Usage

    all.names(expr, functions = TRUE, max.names = -1L, unique = FALSE)

    all.vars(expr, functions = FALSE, max.names = -1L, unique = TRUE)

### Arguments

`expr` | an expression or call from which the names are to be extracted.
`functions` | a logical value indicating whether function names should be included in the result.
`max.names` | the maximum number of names to be returned. `-1` indicates no limit (other than vector size limits).
`unique` | a logical value which indicates whether duplicate names should be removed from the value.

### Details

These functions differ only in the default values for their arguments.

### Value

A character vector with the extracted names.

### See Also

`substitute` to replace symbols with values in an expression.

### Examples

    all.names(expression(sin(x+y)))
    all.names(quote(sin(x+y))) # or a call
    all.vars(expression(sin(x+y)))

[Package base version 2.15.1 Index]