syntax: Selecting Syntax

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Selecting Syntax

Description

Selecting Syntax

Selectors

The cards package also utilizes selectors: selectors from the tidyselect package and custom selectors. Review their help files for details.

• tidy selectors

  everything(), all_of(), any_of(), starts_with(), ends_with(), contains(), matches(), num_range(), last_col()

• cards selectors

  all_ard_groups(), all_ard_variables()

Formula and List Selectors

Some arguments in the cards package accept list and formula notation, e.g. ard_continuous(statistic=). Below enumerates a few tips and shortcuts for using the list and formulas.

1. List of Formulas

   Typical usage includes a list of formulas, where the LHS is a variable name or a selector.

   ard_continuous(statistic = list(age ~ list(N = \(x) length(x)), starts_with("a") ~ list(mean = mean)))
   

2. Named List

   You may also pass a named list; however, the tidyselect selectors are not supported with this syntax.

   ard_continuous(statistic = list(age = list(N = \(x) length(x))))
   

3. Hybrid Named List/List of Formulas

   You can pass a combination of formulas and named elements.

   ard_continuous(statistic = list(age = list(N = \(x) length(x)), starts_with("a") ~ list(mean = mean)))
   

4. Shortcuts

   You can pass a single formula, which is equivalent to passing the formula in a list.

   ard_continuous(statistic = starts_with("a") ~ list(mean = mean)
   

   As a shortcut to select all variables, you can omit the LHS of the formula. The two calls below are equivalent.

   ard_continuous(statistic = ~list(N = \(x) length(x)))
   ard_continuous(statistic = everything() ~ list(N = \(x) length(x)))
   

5. Combination Selectors

   Selectors can be combined using the c() function.

   ard_continuous(statistic = c(everything(), -age) ~ list(N = \(x) length(x)))
   

cards documentation built on Oct. 4, 2024, 1:09 a.m.