R: Data pronouns for tidy evaluation

tidyeval-data {rlang} | R Documentation

## Data pronouns for tidy evaluation

### Description

These pronouns allow you to be explicit about where to find objects when programming with data masked functions.

    m <- 10
    mtcars %>% mutate(disp = .data$disp * .env$m)

- `.data` retrieves data-variables from the data frame.

- `.env` retrieves env-variables from the environment.

Because the lookup is explicit, there is no ambiguity between both kinds of variables. Compare:

    disp <- 10
    mtcars %>% mutate(disp = .data$disp * .env$disp)
    mtcars %>% mutate(disp = disp * disp)

The `.data` object exported from rlang is also useful to import in your package namespace to avoid a `R CMD check` note when referring to objects from the data mask.

Note that `.data` is only a pronoun, it is not a real data frame. This means that you can't take its names or map a function over the contents of `.data`. Similarly, `.env` is not an actual R environment. For instance, it doesn't have a parent and the subsetting operators behave differently.

### Usage

    .data

    .env

### Format

An object of class `rlang_fake_data_pronoun` of length .

[Package rlang version 0.4.3 Index]