R: Class itemsets - A Set of Itemsets

itemsets-class {arules} | R Documentation

## Class itemsets — A Set of Itemsets

### Description

The `itemsets` class represents a set of itemsets and the associated quality measures.

Note that the class can also represent a multiset of itemsets with duplicated elements. Duplicated elements can be removed with `unique`.

### Objects from the Class

Objects are the result of calling the functions `apriori` (e.g., with `target="frequent itemsets"` in the parameter list) or `eclat`. Objects can also be created by calls of the form `new("itemsets", ...)`.

### Slots

`items`:

  object of class `itemMatrix` containing the items in the set of itemsets

`quality`:

  a data.frame containing the quality measures for the itemsets

`tidLists`:

  object of class `tidLists` containing the IDs of the transactions which support each itemset. The slot contains `NULL` if no transactions ID list is available (transactions ID lists are only available for `eclat`).

### Extends

Class `associations`, directly.

### Methods

coerce

  `signature(from = "itemsets", to = "data.frame")`; represent the itemsets in readable form

items

  `signature(x = "itemsets")`; returns the `itemMatrix` representing the set of itemsets

items<-

  `signature(x = "itemsets")`; replaces the `itemMatrix` representing the set of itemsets

itemInfo

  `signature(object = "itemsets")`; returns the whole item information data frame including item labels

labels

  `signature(object = "itemsets")`; returns labels for the itemsets as a character vector. The labels have te following format: "item1, item2,..., itemn"

itemLabels

  `signature(object = "itemsets")`; returns the item labels used to encode the itemsets as a character vector. The index for each label is the column index of the item in the binary matrix.

nitems

  `signature(x = "itemsets")`; number of all possible items in the binary matrix representation of the object.

summary

  `signature(object = "itemsets")`

tidLists

  `signature(object = "itemsets")`; returns the transaction ID list

### Author(s)

Michael Hahsler

### See Also

`[-methods`, `apriori`, `c`, `duplicated`, `eclat`, `inspect`, `is.maximal`, `length`, `match`, `sets`, `size`, `subset`, `associations-class`, `tidLists-class`

### Examples

    data("Adult")

    ## Mine frequent itemsets with Eclat.
    fsets <- eclat(Adult, parameter = list(supp = 0.5))

    ## Display the 5 itemsets with the highest support.
    fsets.top5 <- sort(fsets)[1:5]
    inspect(fsets.top5)

    ## Get the itemsets as a list
    as(items(fsets.top5), "list")

    ## Get the itemsets as a binary matrix
    as(items(fsets.top5), "matrix")

    ## Get the itemsets as a sparse matrix, a ngCMatrix from package Matrix.
    ## Warning: for efficiency reasons, the ngCMatrix you get is transposed
    as(items(fsets.top5), "ngCMatrix")

[Package arules version 1.6-2 Index]