tidyeval-data: '.data' Pronoun
In jesse-smith/covidsms: What the Package Does (One Line, Title Case)

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

1 2	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:

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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.

jesse-smith/covidsms documentation built on Dec. 25, 2021, 4:24 a.m.