Introduction
The teal.slice package provides teal
applications with the filter panel, a powerful tool for
exploring and analyzing data, and a key component of the
teal framework.
One of the great things about the filter panel is that it comes
built-in with teal, requiring no programming knowledge to
use.
The filter panel provides a convenient way for users to subset their data, simplifying the process of exploration and comprehension. Moreover, users can activate or deactivate filter states interactively, either individually or globally, using the filter panel.
Filter flow
%% This is a mermaid diagram, if you see this the plot failed to render. Sorry.
sequenceDiagram
autonumber
data->teal.slice: processed by
teal.slice->>shiny inputs: creates
Note over teal.slice,shiny inputs: based on data type
shiny inputs->>reactive dataset: updates
reactive dataset->>teal modules: processed by
The filter panel creates subsets of data. Subsetting is achieved by
creating filter states, each of which holds a logical predicate (filter
condition) that is applied to single variables. These filter conditions
are composed into a single expression, a call to a particular function
(e.g. dplyr::filter), and that expression is evaluated to
create a filtered data subset.
The process is entirely interactive. Filter states can be created, removed, and changed at will, however, the app developer may choose to constrain or even restrict them.
When a filter state is created, the filter panel generates a
filter card with shiny inputs appropriate to the
type of the variable, e.g. range selectors for numeric columns and sets
of checkboxes or drop-down menus for categorical ones.
As users interact with the filter cards, the subsetting complete expression is updated and filtered data is recomputed.
The filtered data is passed to teal modules for
downstream analysis. The subsetting expression is returned along with
the data, ensuring an unbroken track record of the entire analysis.
Signature of the data are also stored to ensure reproducible
results.