choices_selected: Choices selected

In teal.transform: Functions for Extracting and Merging Data in the 'teal' Framework

Choices selected

Description

Construct a single list containing available choices, the default selected value, and additional settings such as to order the choices with the selected elements appearing first or whether to block the user from making selections.

Can be used in UI input elements such as teal.widgets::optionalSelectInput().

Usage

choices_selected(
  choices,
  selected = if (inherits(choices, "delayed_data")) NULL else choices[1],
  keep_order = FALSE,
  fixed = FALSE
)

is.choices_selected(x)

Arguments

choices	(character) vector of possible choices or delayed_data object. See variable_choices() and value_choices().
selected	(character) vector of preselected options, (all_choices) object or (delayed_data) object. If delayed_data object then choices must also be delayed_data object. If not supplied it will default to the first element of choices if choices is a vector, or NULL if choices is a delayed_data object.
keep_order	(logical) In case of FALSE the selected variables will be on top of the drop-down field.
fixed	(optional logical) Whether to block user to select choices.
x	(choices_selected) object to check.

Details

Please note that the order of selected will always follow the order of choices. The keep_order argument is set to false which will run the following code inside:

choices <- c(selected, setdiff(choices, selected))

In case you want to keep your specific order of choices, set keep_order to TRUE.

Value

choices_selected returns list of choices_selected, encapsulating the specified choices, selected, keep_order and fixed.

is.choices_selected returns TRUE if x inherits from a choices_selected object, FALSE otherwise.

Functions

• is.choices_selected(): Check if an object is a choices_selected class

Examples

library(shiny)
library(teal.widgets)

# all_choices example - semantically the same objects
choices_selected(choices = letters, selected = all_choices())
choices_selected(choices = letters, selected = letters)

choices_selected(
  choices = setNames(LETTERS[1:5], paste("Letter", LETTERS[1:5])),
  selected = "C"
)

ADSL <- teal.transform::rADSL
choices_selected(variable_choices(ADSL), "SEX")

# How to select nothing
# use an empty character
choices_selected(
  choices = c("", "A", "B", "C"),
  selected = ""
)

# How to allow the user to select nothing
# use an empty character
choices_selected(
  choices = c("A", "", "B", "C"),
  selected = "A"
)


# How to make Nothing the Xth choice
# just use keep_order
choices_selected(
  choices = c("A", "", "B", "C"),
  selected = "A",
  keep_order = TRUE
)


# How to give labels to selections
# by adding names - choices will be replaced by "name" in UI, not in code
choices_selected(
  choices = c("name for A" = "A", "Name for nothing" = "", "name for b" = "B", "name for C" = "C"),
  selected = "A"
)

# by using choices_labeled
# labels will be shown behind the choice
choices_selected(
  choices = choices_labeled(
    c("A", "", "B", "C"),
    c("name for A", "nothing", "name for B", "name for C")
  ),
  selected = "A"
)

# Passing a `delayed_data` object to `selected`
choices_selected(
  choices = variable_choices("ADSL"),
  selected = variable_choices("ADSL", subset = c("STUDYID"))
)

# functional form (subsetting for factor variables only) of choices_selected
# with delayed data loading
choices_selected(variable_choices("ADSL", subset = function(data) {
  idx <- vapply(data, is.factor, logical(1))
  names(data)[idx]
}))

cs <- choices_selected(
  choices = c("A", "B", "C"),
  selected = "A"
)

ui <- fluidPage(
  optionalSelectInput(
    inputId = "id",
    choices = cs$choices,
    selected = cs$selected
  )
)

server <- function(input, output, session) {}
if (interactive()) {
  shinyApp(ui, server)
}

teal.transform documentation built on May 29, 2024, 5:06 a.m.