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 0.6-3 Index]