FilterState: 'FilterState' abstract class

In teal.slice: Filter Module for 'teal' Applications

FilterState abstract class

Description

Abstract class to encapsulate single filter state.

Details

This class is responsible for managing a single filter item within a FilteredData object and outputs a condition call (logical predicate) for subsetting one variable. Filter states depend on the variable type: (logical, integer, numeric, character, factor, Date, POSIXct, POSIXlt) and FilterState subclasses exist that correspond to those types.

• logical: class = LogicalFilterState

• integer: class = RangeFilterState

• numeric: class = RangeFilterState

• character: class = ChoicesFilterState

• factor: class = ChoicesFilterState

• Date: class = DateFilterState

• POSIXct, POSIXlt: class = DatetimeFilterState

• all NA entries: class: FilterState, cannot be filtered

• default: FilterState, cannot be filtered

Each variable's filter state is an R6 object keeps the variable that is filtered, a teal_slice object that describes the filter state, as well as a shiny module (UI and server) that allows the user to alter the filter state. Changes to the filter state that cause some observations to be omitted trigger the get_call method and every R function call up in the reactive chain.

Modifying state

Modifying a FilterState object is possible in three scenarios:

• In an interactive session, by passing an appropriate teal_slice to the set_state method.

• In a running application, by changing appropriate inputs.

• In a running application, by using filter_state_api which directly uses set_state method of the FilterState object.

Methods

Public methods

• FilterState$new()

• FilterState$format()

• FilterState$print()

• FilterState$set_state()

• FilterState$get_state()

• FilterState$get_call()

• FilterState$server()

• FilterState$ui()

• FilterState$destroy_observers()

• FilterState$clone()

---

Method new()

Initialize a FilterState object.

Usage

FilterState$new(
  x,
  x_reactive = reactive(NULL),
  slice,
  extract_type = character(0)
)

Arguments

x

(vector) variable to be filtered.

x_reactive

(reactive) returning vector of the same type as x. Is used to update counts following the change in values of the filtered dataset. If it is set to reactive(NULL) then counts based on filtered dataset are not shown.

slice

(teal_slice) specification of this filter state. teal_slice is stored in the object and set_state directly manipulates values within teal_slice. get_state returns teal_slice object which can be reused in other places. Note that teal_slice is a reactiveValues, which means it has reference semantics, i.e. changes made to an object are automatically reflected in all places that refer to the same teal_slice.

extract_type

(character) specifying whether condition calls should be prefixed by dataname. Possible values:

• character(0) (default) varname in the condition call will not be prefixed

• "list" varname in the condition call will be returned as ⁠<dataname>$<varname>⁠

• "matrix" varname in the condition call will be returned as ⁠<dataname>[, <varname>]⁠

Returns

Object of class FilterState, invisibly.

---

Method format()

Returns a formatted string representing this FilterState object.

Usage

FilterState$format(show_all = FALSE, trim_lines = TRUE)

Arguments

show_all

(logical(1)) passed to format.teal_slice

trim_lines

(logical(1)) passed to format.teal_slice

Returns

character(1) the formatted string

---

Method print()

Prints this FilterState object.

Usage

FilterState$print(...)

Arguments

...

additional arguments

---

Method set_state()

Sets mutable parameters of the filter state.

• fixed state is prevented from changing state

• anchored state is prevented from removing state

Usage

FilterState$set_state(state)

Arguments

state

(teal_slice)

Returns

self invisibly

---

Method get_state()

Returns a complete description of the filter state.

Usage

FilterState$get_state()

Returns

A teal_slice object.

---

Method get_call()

Returns reproducible condition call for current selection relevant for selected variable type. Method is using internal reactive values which makes it reactive and must be executed in reactive or isolated context.

Usage

FilterState$get_call()

---

Method server()

shiny module server.

Usage

FilterState$server(id)

Arguments

id

(character(1)) shiny module instance id.

Returns

Reactive expression signaling that remove button has been clicked.

---

Method ui()

shiny UI module. The UI for this class contains simple message stating that it is not supported.

Usage

FilterState$ui(id, parent_id = "cards")

Arguments

id

(character(1)) shiny module instance id.

parent_id

(character(1)) id of the FilterStates card container

---

Method destroy_observers()

Destroy observers stored in private$observers.

Usage

FilterState$destroy_observers()

Returns

NULL, invisibly.

---

Method clone()

The objects of this class are cloneable with this method.

Usage

FilterState$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

teal.slice documentation built on May 29, 2024, 1:39 a.m.