size-methods {arulesSequences}

Compute the Size of Sequences

Description

size computes the size of a sequence. This can be either the number of (distinct) itemsets (elements) or items occurring in a sequence.

ritems compute the minimum (maximum) number an item or itemset (element) is repeatedly occurring in a sequence.

Usage

## S4 method for signature 'sequences'
size(x, type = c("size", "itemsets", "length", "items"))

## S4 method for signature 'sequences'
ritems(x, type = c("min", "max"), itemsets = FALSE)

Arguments

x

an object.

type, itemsets

as string (logical) value specifying the type of count to be computed.

Value

Returns a vector of counts corresponding with the elements of object x.

Note

The total number of items occurring in a sequence is often referred to as the length of the sequence. Similarly, we refer to the total number of itemsets as the size of the sequence. Note that we follow this terminology in the summary methods.

For use with a collection of rules use the accessors lhs or rhs, or coerce to sequences.

Author(s)

Christian Buchta

See Also

Class sequences, timedsequences.

Examples

## continue example
example(cspade)

## default size
size(s2)
size(s2, "itemsets")
size(s2, "length")
size(s2, "items")

## crosstab
table(length = size(s1, "length"),
      items  = size(s1, "items"))

## repetitions
ritems(s1)
ritems(s1, "max")
ritems(s1, "max", TRUE)