APappearance-class {arules}R Documentation

Class “APappearance” — Specifying the ‘appearance’ Argument of apriori()

Description

Specifies the restrictions on the associations mined by apriori. Note that appearance is not supported by the implementation of eclat.

Objects from the Class

If appearance restrictions are used, an appearance object will be created automatically within the apriori function using the information in the named list of the function's appearance argument. In this case, the item labels used in the list will be automatically matched against the items in the used transaction database. The list can contain the following elements:

default:

one of "both", "lhs", "rhs", "none" (the default is "both"). This element specified the default appearance for all items not explicitly mentioned in the other elements of the list.

lhs, rhs, both, none, items:

character vectors giving the labels of the items which may only appear in the corresponding place of the rules/itemsets.

Objects can also be created by calls of the form new("APappearance", ...). In this case, item IDs (column numbers of the transactions incidence matrix) have to be used instead of labels.

Slots

set:

an integer scalar indicating how many items are specified for each of lhs, rhs, items, both and none

items:

an integer vector of item IDs (column numbers)

labels:

a character vector of item labels

default:

a character scalar indicating the value for default appearance

References

Christian Borgelt (2004) Apriori — Finding Association Rules/Hyperedges with the Apriori Algorithm. http://fuzzy.cs.uni-magdeburg.de/~borgelt/apriori.html

See Also

apriori

Examples

data("Adult")
## Mine only rules with small or large income in the right-hand-side.
rules <- apriori(Adult, parameter = list(confidence = 0.5), 
  appearance = list(rhs = c("income=small", "income=large"),
  default="lhs"))

[Package arules version 1.0-7 Index]