subset {arules}R Documentation

Subsetting Itemsets, Rules and Transactions

Description

Provides the generic function subset and S4 methods to subset associations or transactions (itemMatrix) which meet certain conditions (e.g., contains certain items or satisfies a minimum lift).

Usage

subset(x, ...)

## S4 method for signature 'itemMatrix'
subset(x, subset, ...)

## S4 method for signature 'itemsets'
subset(x, subset, ...)

## S4 method for signature 'rules'
subset(x, subset, ...)

## S4 method for signature 'itemMatrix'
subset(x, subset, ...)

Arguments

x

object to be subsetted.

subset

logical expression indicating elements to keep.

...

further arguments to be passed to or from other methods.

Details

subset works on the rows/itemsets/rules of x. The expression given in subset will be evaluated using x, so the items (lhs/rhs/items) and the columns in the quality data.frame can be directly referred to by their names.

Important operators to select itemsets containing items specified by their labels are %in% (select itemsets matching any given item), %ain% (select only itemsets matching all given item), %oin% (select only itemsets matching only the given item), and %pin% (%in% with partial matching).

Value

An object of the same class as x containing only the elements which satisfy the conditions.

Author(s)

Michael Hahsler

See Also

%in%, %pin%, %ain%, %oin%, itemMatrix-class, itemsets-class, rules-class, transactions-class

Examples

data("Adult")
rules <- apriori(Adult)

## select all rules with item "marital-status=Never-married" in 
## the right-hand-side and lift > 2
rules.sub <- subset(rules, subset = rhs %in% "marital-status=Never-married" 
    & lift > 2)

## use partial matching for all items corresponding to the variable
## "marital-status"
rules.sub <- subset(rules, subset = rhs %pin% "marital-status=")

## select only rules with items "age=Young" and "workclass=Private" in
## the left-hand-side
rules.sub <- subset(rules, subset = lhs %ain% 
    c("age=Young", "workclass=Private"))

[Package arules version 1.7-1 Index]