teal.transform (version 0.6.0)

delayed_choices: Bare constructor for delayed_choices object

Description

Special S3 structures that delay selection of possible choices in a filter_spec, select_spec or choices_selected object.

Usage

all_choices()
first_choice()
last_choice()
first_choices(n)
last_choices(n)

Value

Object of class delayed_data, delayed_choices, which is a function that returns the appropriate subset of its argument. all_choices, first_choices, and last_choices structures also have an additional class for internal use.

Arguments

n

positive (integer-like) number of first/last items to subset to

Examples

# These pairs of structures represent semantically identical specifications:
choices_selected(choices = letters, selected = letters)
choices_selected(choices = letters, selected = all_choices())

choices_selected(choices = letters, selected = letters[1])
choices_selected(choices = letters, selected = first_choice())

choices_selected(choices = letters, selected = letters[length(letters)])
choices_selected(choices = letters, selected = last_choice())

choices_selected(choices = letters, selected = head(letters, 4))
choices_selected(choices = letters, selected = first_choices(4))

choices_selected(choices = letters, selected = tail(letters, 4))
choices_selected(choices = letters, selected = last_choices(4))

filter_spec(
  vars = c("selected_variable"),
  choices = c("value1", "value2", "value3"),
  selected = "value3"
)
filter_spec(
  vars = c("selected_variable"),
  choices = c("value1", "value2", "value3"),
  selected = last_choice()
)