arules (version 1.0-12)

subset: 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, ...)
## S3 method for class 'itemMatrix':
subset(x, subset, ...)
## S3 method for class 'itemsets':
subset(x, subset, ...)
## S3 method for class 'rules':
subset(x, subset, ...)
## S3 method for class '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.

Value

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

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) and %pin% (%in% with partial matching).

See Also

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"))