APappearance-class: Class ``APappearance'' --- Specifying the `appearance' Argument of apriori() to Implement Rule Templates

Description

Specifies the restrictions on the associations mined by apriori. These restrictions can implement certain aspects of rule templates described by Klemettinen (1994). Note that appearance is only supported by the implementation of apriori.

Arguments

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:

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

References

Christian Borgelt (2004) Apriori --- Finding Association Rules/Hyperedges with the Apriori Algorithm. www.borgelt.net/apriori.html

M. Klemettinen, H. Mannila, P. Ronkainen, H. Toivonen and A. I. Verkamo (1994). Finding Interesting Rules from Large Sets of Discovered Association Rules. In Proceedings of the Third International Conference on Information and Knowledge Management, 401--407.

Examples

Run this code

data("Adult")

## find only frequent itemsets which do not contain  small or large income
is <- apriori(Adult, parameter = list(support= 0.1, target="frequent"), 
  appearance = list(none = c("income=small", "income=large"),
  default="both"))
itemFrequency(items(is))["income=small"]
itemFrequency(items(is))["income=large"]

## find itemsets that only contain small or large income and young age
is <- apriori(Adult, parameter = list(support= 0.1, target="frequent"), 
  appearance = list(items = c("income=small", "income=large", "age=Young"),
  default="none"))
inspect(head(is))
  
## find only rules with small or large income in the right-hand-side.
rules <- apriori(Adult, parameter = list(support=0.2, confidence = 0.5), 
  appearance = list(rhs = c("income=small", "income=large"),
  default="lhs"))
inspect(head(rules))

## for more complicated restrictions you have to mine all rules/itemsets and
## then filter the results afterwards