R: Create a dictionary

dictionary {rlang} | R Documentation

## Create a dictionary

### Description

Dictionaries are a concept of types modelled after R environments. Dictionaries are containers of R objects that:

- Contain uniquely named objects.

- Can only be indexed by name. They must implement the extracting operators `$` and `[[`. The latter returns an error when indexed by position because dictionaries are not vectors (they are unordered).

- Report a clear error message when asked to extract a name that does not exist. This error message can be customised with the `lookup_msg` constructor argument.

### Usage

    as_dictionary(x, lookup_msg = NULL, read_only = FALSE)

    is_dictionary(x)

### Arguments

`x` | An object for which you want to find associated data.
`lookup_msg` | An error message when your data source is accessed inappropriately (by position rather than name).
`read_only` | Whether users can replace elements of the dictionary.

### Details

Dictionaries are used within the tidy evaluation framework for creating pronouns that can be explicitly referred to from captured code. See `eval_tidy()`.

[Package rlang version 0.1.6 Index]