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
(see Examples section) or by
calls of the form new("transactions", ...)
.
transactionInfo
:a data.frame with vectors of the same length as the number of transactions. Each vector can hold additional information, e.g., store transaction IDs or user IDs for each transaction.
data
:object of class
ngCMatrix
to store the
binary incidence matrix (see
itemMatrix
class)
itemInfo
:a data.frame to store
item labels (see 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")
;
coerces the transactions data set into a binary incidence matrix.
signature(from = "transactions", to = "list")
;
coerces the transactions data set into a list of transactions.
Each transaction is a vector of character strings (names of the
contained items).
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
.
Note that NA
in one of the levels is replaced by the string
“NA”, i.e. the special meaning is lost.
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 frame
signature(x = "transactions")
;
returns transactionInfo
signature(object = "transactions")
signature(object = "transactions")
[-methods
,
LIST
,
WRITE
,
c
,
image
,
inspect
,
read.transactions
,
random.transactions
,
sets
,
itemMatrix-class
## example 1: 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) ## example 2: 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 inspect(trans2) ## example 3: creating transactions from data.frame a_df <- 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_df ## coerce trans3 <- as(a_df, "transactions") image(trans3) ## example 4: Creating from data.frame with NA a_df2 <- sample(c(LETTERS[1:5], NA),10,TRUE) a_df2 <- data.frame(X = a_df2, Y = sample(a_df2)) a_df2 trans3 <- as(a_df2, "transactions") trans3 as(trans3, "data.frame") ## example 5: creating transactions from a data.frame with ## transaction IDs and items a_df3 <- data.frame(TID = c(1,1,2,2,2,3), item=c("a","b","a","b","c", "b")) a_df3 trans4 <- as(split(a_df3[,"item"], a_df3[,"TID"]), "transactions") trans4 LIST(trans4)