R: Class associations - A Set of Associations

associations-class {arules} | R Documentation

## Class associations - A Set of Associations

### Description

The `associations` class is a virtual class which is extended to represent mining result (e.g., sets of `itemsets` or `rules`). The class provides accessors for the quality slot and a method for sorting the associations.

### Details

The implementations of `associations` store itemsets (e.g., the LHS and RHS of a rule) as objects of class `itemMatrix` (i.e., sparse binary matrices). Quality measures (e.g., support) are stored in a data.frame accessable via method `quality`.

Associations can store multisets with duplicated elements. Duplicated elements can result from combining several sets of associations. Use `unique` to remove duplicate associations.

### Objects from the Class

A virtual class: No objects may be created from it.

### Slots

`quality`:

  a data.frame for quality measures (e.g., interest measures as support or confidence). Each quality measure is a named vector with the same length as the number of elements in the set of associations and each vector element belongs to the association with the same index.

`info`:

  a list which is used to store algorithm specific mining information. Typically it contains a least the elements `"data"` (name of the transaction data set), `"ntransactions"` (length of the data set), `"support"` (the minimum support used for mining).

### Methods

info<-

  `signature(x = "associations")`; replaces the info list.

info

  `signature(x = "associations")`; returns the info list.

items

  `signature(x = "associations")`; dummy method. This method has to be implemented by all subclasses of `associations` and return the items which make up each association as an object of class `itemMatrix`.

labels

  `signature(object = "associations")`; dummy method. This method has to be implemented by all subclasses of `associations` and return a vector of `length(object)` of labels for the elements in the association.

length

  `signature(x = "associations")`; dummy method. This method has to be implemented by all subclasses of `associations` and return the number of elements in the association.

quality<-

  `signature(x = "associations")`; replaces the quality data.frame. The lengths of the vectors in the data.frame have to equal the number of associations in the set.

quality

  `signature(x = "associations")`; returns the quality data.frame.

show

  `signature(object = "associations")`

### Subclasses

`itemsets-class`, `rules-class`

### Author(s)

Michael Hahsler

### See Also

`sort`, `write`, `length`, `is.subset`, `is.superset`, `sets`, `unique`, `itemMatrix-class`

[Package arules version 1.6-7 Index]