subset {arules} | R Documentation |
Provides the generic function subset()
and methods to subset
associations or transactions (itemMatrix) which meet certain conditions
(e.g., contains certain items or satisfies a minimum lift).
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, ...)
x |
object to be subsetted. |
... |
further arguments to be passed to or from other methods. |
subset |
logical expression indicating elements to keep. |
subset()
finds the rows/itemsets/rules of x
that match the expression
given in subset
. Parts of x
like items, lhs, rhs and the columns in the quality data.frame (e.g., support and lift) can be directly referred to by their names
in subset
.
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
%pin%: %in%
with partial matching
An object of the same class as x
containing only the elements
which satisfy the conditions.
Michael Hahsler
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"))