dot-determine_choices: Evaluate delayed choices

In teal.picks: Dataset and Variable Picker and Merge Module for 'teal' Applications

Evaluate delayed choices

Description

Evaluate delayed choices

Usage

.determine_choices(x, data)

.determine_selected(x, data, multiple = FALSE, warn = TRUE)

.determine_delayed(x, data)

.possible_choices(data)

Arguments

x	(character, quosure, ⁠function(x)⁠) to determine data elements to extract.
data	(list, data.frame, vector)
multiple	(logical(1)) whether multiple selection is possible.

Details

Various ways to evaluate choices/selected.

Function resolves x to determine choices or selected. x is matched in multiple ways with data to return valid choices:

• x (character): values are matched with names of data and only intersection is returned.

• x (tidyselect-helper): using tidyselect::eval_select

• ⁠x (function)⁠: function is executed on each element of data to determine where function returns TRUE

Mechanism is robust in a sense that it never fails (tryCatch) and returns NULL if no-match found. NULL in determine() is handled gracefully, by setting NULL to all following components of picks.

In the examples below you can replace .determine_delayed with .determine_choices or .determine_selected.

• character: refers to the object name in data, for example

  .determine_delayed(data = iris, x = "Species")
  .determine_delayed(data = iris, x = c("Species", "inexisting"))
  .determine_delayed(data = list2env(list(iris = iris, mtcars = mtcars)), x = "iris")
  

• quosure: delayed (quoted) tidyselect-helper to be evaluated through tidyselect::eval_select. For example

  .determine_delayed(data = iris, x = rlang::quo(tidyselect::starts_with("Sepal")))
  .determine_delayed(data = iris, x = rlang::quo(1:2))
  .determine_delayed(data = iris, x = rlang::quo(Petal.Length:Sepal.Length))
  

• ⁠function(x)⁠: predicate function returning a logical flag. Evaluated for each data element. For example

  .determine_delayed(data = iris, x = is.numeric)
  .determine_delayed(data = letters, x = function(x) x > "c")
  .determine_delayed(data = list2env(list(iris = iris, mtcars = mtcars, a = "a")), x = is.data.frame)
  

Value

character containing names/levels of data elements which match x, with two differences:

• .determine_choices returns vector named after data labels

• .determine_selected cuts vector to scalar when multiple = FALSE

teal.picks documentation built on Oct. 9, 2026, 5:07 p.m.