is.generator: Find Generator Itemsets

In arules: Mining Association Rules and Frequent Itemsets

Find Generator Itemsets

Description

Provides the generic function and the method 'is.generator() for finding generator itemsets. Generators are part of concise representations for frequent itemsets. A generator in a set of itemsets is an itemset that has no subset with the same support (Liu et al, 2008). Note that the empty set is by definition a generator, but it is typically not stored in the itemsets in arules.

Usage

is.generator(x)

## S4 method for signature 'itemsets'
is.generator(x)

Arguments

x	a set of itemsets.

Value

a logical vector with the same length as x indicating for each element in x if it is a generator itemset.

Author(s)

Michael Hahsler

References

Yves Bastide, Niolas Pasquier, Rafik Taouil, Gerd Stumme, Lotfi Lakhal (2000). Mining Minimal Non-redundant Association Rules Using Frequent Closed Itemsets. In International Conference on Computational Logic, Lecture Notes in Computer Science (LNCS 1861). pages 972–986. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1007/3-540-44957-4_65")}

Guimei Liu, Jinyan Li, Limsoon Wong (2008). A new concise representation of frequent itemsets using generators and a positive border. Knowledge and Information Systems 17(1):35-56. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1007/s10115-007-0111-5")}

See Also

Other postprocessing: is.closed(), is.maximal(), is.redundant(), is.significant(), is.superset()

Other associations functions: abbreviate(), associations-class, c(), duplicated(), extract, inspect(), is.closed(), is.maximal(), is.redundant(), is.significant(), is.superset(), itemsets-class, match(), rules-class, sample(), sets, size(), sort(), unique()

Examples

# Example from Liu et al (2008)
trans_list <- list(
      t1 = c("a","b","c"),
      t2 = c("a","b", "c", "d"),
      t3 = c("a","d"),
      t4 = c("a","c")
      )

trans <- transactions(trans_list)
its <- apriori(trans, support = 1/4, target = "frequent itemsets")

is.generator(its)

arules documentation built on Sept. 11, 2024, 8:15 p.m.