Data block constructors — new_data

Data blocks typically do not have data inputs and represent root nodes in analysis graphs. Intended as initial steps in a pipeline, such blocks are responsible for providing down-stream blocks with data.

Usage

new_data_block(server, ui, class, ctor = sys.parent(), ...)

new_dataset_block(dataset = character(), package = "datasets", ...)

new_static_block(data, ...)

Arguments

server: A function returning shiny::moduleServer()
ui: A function with a single argument (ns) returning a shiny.tag
class: Block subclass
ctor: String-valued constructor name or function/frame number (mostly for internal use or when defining constructors for virtual classes)
...: Forwarded to new_data_block() and new_block()
dataset: Selected dataset
package: Name of an R package containing datasets
data: Data (used directly as block result)

Value

All blocks constructed via new_data_block() inherit from data_block.

Dataset block

This data block allows to select a dataset from a package, such as the datasets package available in most R installations as one of the packages with "recommended" priority. The source package can be chosen at time of block instantiation and can be set to any R package, for which then a set of candidate datasets is computed. This includes exported objects that inherit from data.frame.

Static block

Mainly useful for testing and examples, this block simply returns the data with which it was initialized. Serialization of static blocks is not allowed and exported code will not be self-contained in the sense that it will not be possible to reproduce results in a script that contains code from a static block.