embrace-operator: Embrace operator {{

In rlang: Functions for Base Types and Core R and 'Tidyverse' Features

Embrace operator ⁠{{⁠

Description

The embrace operator ⁠{{⁠ is used to create functions that call other data-masking functions. It transports a data-masked argument (an argument that can refer to columns of a data frame) from one function to another.

my_mean <- function(data, var) {
  dplyr::summarise(data, mean = mean({{ var }}))
}

Under the hood

⁠{{⁠ combines enquo() and !! in one step. The snippet above is equivalent to:

my_mean <- function(data, var) {
  var <- enquo(var)
  dplyr::summarise(data, mean = mean(!!var))
}

See Also

• What is data-masking and why do I need {{?

• Data mask programming patterns

rlang documentation built on Nov. 4, 2023, 9:06 a.m.