| transactions-class {arules} | R Documentation |
The transactions class represents transaction data used for
mining itemsets or rules. It is a direct extension of class
itemMatrix to store a binary incidence
matrix, item labels, and optionally transaction IDs and user IDs.
Objects are created by coercion from objects of other classes or by
calls of the form new("transactions", ...).
transactionInfo:data:ngCMatrix to store the
binary incidence matrix (see
itemMatrix class)itemInfo:itemMatrix class)
Class itemMatrix, directly.
signature(from = "matrix", to = "transactions");
produces a transactions data set from a binary incidence matrix.
The row names are used as item labels and the column names are
stores as transaction IDs.
signature(from = "list", to = "transactions");
produces a transactions data set from a list. The names of the
items in the list are used as item labels and the item IDs and the
incidence matrix is produced automatically.
signature(from = "transactions", to = "matrix")signature(from = "transactions", to = "list")signature(from = "data.frame", to = "transactions");
recodes the data frame containing only categorical variables (all
have to be factors) into a binary transaction data set. The needed
number of dummy items are automatically generated. The item
labels are generated by concatenating variable names and levels with
a "=".
The variable names and levels are stored in the labels data frame
as the components variables and levels.signature(from = "transactions", to = "data.frame");
represents the set of transactions in a printable form
as a data.frame.
Note that this does not reverse coercion from data.frame
to transactions.signature(x = "transactions");
returns the labels (item labels and transaction IDs)
for the incidence matrix as a list of two vectors named items
and transactionID.signature(x = "transactions");
replaces the transactionInfo data framesignature(x = "transactions");
returns transactionInfosignature(object = "transactions")signature(object = "transactions")
[-methods,
LIST,
WRITE,
c,
image,
inspect,
read.transactions,
random.transactions,
sets,
itemMatrix-class
### 1. example: creating transactions form a list
a_list <- list(
c("a","b","c"),
c("a","b"),
c("a","b","d"),
c("c","e"),
c("a","b","d","e")
)
# set transaction names
names(a_list) <- paste("Tr",c(1:5), sep = "")
a_list
# coerce into transactions
trans <- as(a_list, "transactions")
# analyze transactions
summary(trans)
image(trans)
### 2. example: creating transactions from a matrix
a_matrix <- matrix(
c(1,1,1,0,0,
1,1,0,0,0,
1,1,0,1,0,
0,0,1,0,1,
1,1,0,1,1), ncol = 5)
# set dim names
dimnames(a_matrix) <- list(
c("a","b","c","d","e"),
paste("Tr",c(1:5), sep = ""))
a_matrix
# coerce
trans2 <- as(a_matrix, "transactions")
trans2
### example 3: creatring transactions from data.frame
a_data.frame <- data.frame(
age = as.factor(c(6,8,7,6,9,5)),
grade = as.factor(c(1,3,1,1,4,1)))
# note: all attributes have to be factors
a_data.frame
# coerce
trans3 <- as(a_data.frame, "transactions")
image(trans3)