ASTVariable: A Variable in an Abstract Syntax Tree (AST)

In tangram: The Grammar of Tables

A Variable in an Abstract Syntax Tree (AST)

Description

A Variable in an Abstract Syntax Tree (AST)

A Variable in an Abstract Syntax Tree (AST)

Format

R6Class object.

Details

This node represents a variable of interest in the AST. A variable's name is recorded in the value field, and must conform to the rules of identifiers in R. This class inherits from ASTNode.

Methods

new(identifier, format=NA, type=NA)

terms()

Returns the node

distribute()

Applies the distributive property to the node, and returns the resulting node.

string()

Returns the string formula of the node

name()

Return a human representation of a node

reduce(data)

Given a set of data, perform the logical reduction of the current node.

Super class

tangram::ASTNode -> ASTVariable

Public fields

data

The associated data post reduction

type

The identified type of this node (defaults: Categorical, Numeric)

Methods

Public methods

• ASTVariable$new()

• ASTVariable$factors()

• ASTVariable$name()

• ASTVariable$string()

• ASTVariable$reduce()

• ASTVariable$clone()

Inherited methods

• tangram::ASTNode$distribute()
• tangram::ASTNode$set_format()
• tangram::ASTNode$terms()

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Method new()

This method creates an AST node representing a variable of a given identifier. An optional format consisting of a string of a number or a c-style printf string. An option type denoting a forced type cast of that variable.

Usage

ASTVariable$new(identifier, format = NA, type = NA)

Arguments

identifier

(character) Variable name

format

(character, numeric) Formatting directive

type

(character) any additional type information

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Method factors()

Returns all terminal nodes under this. Since this is a terminal node, returns self

Usage

ASTVariable$factors()

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Method name()

Returns the text name of this node. For an intercept, returns "All"

Usage

ASTVariable$name()

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Method string()

Returns name of variable with optional format and type information

Usage

ASTVariable$string()

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Method reduce()

Given a data.frame, associates correct variable with this node

Usage

ASTVariable$reduce(d)

Arguments

d

(data.frame) data.frame to reduce

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Method clone()

The objects of this class are cloneable with this method.

Usage

ASTVariable$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

Examples

ASTVariable$new("x", "2", "Continuous")$string()

tangram documentation built on Feb. 16, 2023, 5:59 p.m.