R: Build a formula using 'tidyselect'-style selection helpers

tidyformula {tidyformula}

R Documentation

Build a formula using `tidyselect`-style selection helpers

Description

tidyformula() translates formulas containing tidyselect-style selection helpers, expanding these helpers by evaluating dplyr::select() with the relevant selection helper and a supplied data frame.

When the selection helper appears as the first argument of a function, that function is distributed across the sum of the selected variables.

Usage

tidyformula(
  formula,
  data,
  select_helpers = .select_helpers,
  nodistribute = c("+", "-", "*", "^"),
  env = rlang::caller_env()
)

Arguments

`formula`	An object of class `formula`. Can contain selection helpers to be expanded.
`data`	A data frame whose column names should be used for selection
`select_helpers`	A character vector. The names of selection helpers to be matched and substituted.
`nodistribute`	A character vector. Functions with these names are not distributed over selection helpers.
`env`	The environment to associate with the result.

Value

An object of class formula, which is a translation of the argument formula in which the selection helpers are replaced with the corresponding variables of data.

Examples

df <- data.frame(
  x1 = rnorm(5),
  x2 = rnorm(5),
  x3 = rnorm(5),
  y  = rnorm(5)
)

tidyformula(y ~ num_range("x", 1:2) + z, data = df)
#> y ~ x1 + x2 + z
#> <environment: 0x000001e0d7d53910>

tidyformula(y ~ poly(starts_with("x"), 3), data = df)
#> y ~ poly(x1, 3) + poly(x2, 3) + poly(x3, 3)
#> <environment: 0x000001e0d7d53910>

tidyformula( ~ everything() * contains("x"), data = df)
#> ~(x1 + x2 + x3 + y) * (x1 + x2 + x3)
#> <environment: 0x000001e0d7d53910>

Interaction operators are typically not distributed, but this behaviour can be changed.

tidyformula(y ~ starts_with("x")^2, data = df)
#> y ~ (x1 + x2 + x3)^2
#> <environment: 0x000001e0d7d53910>

tidyformula(y ~ starts_with("x")^2, data = df, nodistribute = c("+", "-"))
#> y ~ x1^2 + x2^2 + x3^2
#> <environment: 0x000001e0d7d53910>