arulesCBA: classFrequency – R documentation

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classFrequency

Extracting the Response and Class Frequency for Transactions or CAR Sets

Description

Converts the class items in transactions/CARs back to a class label. Class frequency can be used to check transactions for class imbalance or the proportion of rules for each class label in a set of CARs.

Usage

response(formula, x)
classFrequency(formula, x, type = "relative")
majorityClass(formula, transactions)

Arguments

`formula`	A symbolic description of the model to be fitted.
`x, transactions`	An object of class `transactions` or `rules`.
`type`	`"relative"` or `"absolute"` to return proportions or absolute counts.

Value

response returns the response label as a factor.

classFrequency returns the item frequency for each class label as a vector.

majorityClass returns the most frequent class label in the transactions.

Author(s)

Michael Hahsler

Examples

data("iris")

iris.disc <- discretizeDF.supervised(Species ~ ., iris)
iris.trans <- as(iris.disc, "transactions")
inspect(head(iris.trans, n = 2))

# convert the class items back to a class label
response(Species ~ ., head(iris.trans, n = 2))

# Class distribution. The iris dataset is perfectly balanced.
classFrequency(Species ~ ., iris.trans)

# Majority Class
# (Note: since all class frequencies for iris are the same, the first one is returned)
majorityClass(Species ~ ., iris.trans)

# Use for CARs
cars <- mineCARs(Species ~ ., iris.trans, parameter = list(support = 0.3))

# Number of rules for each class
classFrequency(Species ~ ., cars, type = "absolute")

# conclusion (item in the RHS) of the rule as a class label
response(Species ~ ., head(iris.trans, n = 2))

arulesCBA

Classification Based on Association Rules

v1.2.0

GPL-3

Authors

Michael Hahsler [aut, cre, cph], Ian Johnson [aut, cph], Tyler Giallanza [ctb]

Initial release

2020-4-17