tidLists-class {arules} | R Documentation |
Transaction ID lists contains a set of lists. Each list is associated with
an item/itemset and stores the IDs of the transactions which support the
item/itemset. tidLists
uses the class
ngCMatrix
to efficiently store the
transaction ID lists as a sparse matrix. Each column in the matrix
represents one transaction ID list.
tidLists
can be used for different purposes. For some operations
(e.g., support counting) it is efficient to coerce a
transactions
database into tidLists
where each
list contains the transaction IDs for an item (and the support is given by
the length of the list).
The implementation of the Eclat mining algorithm (which uses transaction ID
list intersection) can also produce transaction ID lists for the found
itemsets as part of the returned itemsets
object. These
lists can then be used for further computation.
Objects are created by Eclat if the eclat
function is called
with tidLists = TRUE
in the ECparameter
object,
and returned as part of the mined itemsets
. Objects can
also be created by coercion from an object of class
transactions
or by calls of the form
new("tidLists", ...)
.
data
:object of class
ngCMatrix
.
itemInfo
:a data.frame to store item/itemset labels (see
itemMatrix
class).
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.
signature(from = "tidLists", to = "ngCMatrix")
;
access the sparse matrix representation. In the
ngCMatrix
each column represents the transaction IDs
for one item/itemset.
signature(from = "tidLists", to = "dgCMatrix")
signature(from = "tidLists", to = "list")
signature(from = "tidLists", to = "matrix")
signature(from = "tidLists", to = "itemMatrix")
signature(from = "tidLists", to = "transactions")
signature(from = "itemMatrix", to = "tidLists")
signature(from = "transactions", to = "tidLists")
signature(x = "tidLists")
;
returns the dimensions of the sparse Matrix representing the
tidLists
.
returns the slot itemInfo
.
signature(object = "tidLists")
;
returns the item labels as a character vector.
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(object = "tidLists")
signature(object = "tidLists")
signature(x = "transactions")
:
returns the slot transactionInfo
.
[-methods
,
LIST
,
eclat
,
image
,
length
,
size
,
ngCMatrix
(in Matrix),
itemMatrix-class
,
itemsets-class
,
transactions-class
## Create transaction data set. data <- list( c("a","b","c"), c("a","b"), c("a","b","d"), c("b","e"), c("b","c","e"), c("a","d","e"), c("a","c"), c("a","b","d"), c("c","e"), c("a","b","d","e") ) t <- as(data, "transactions") ## Mine itemsets with tidLists. f <- eclat(data, parameter = list(support = 0, tidLists = TRUE)) ## Get dimensions of the tidLists. dim(tidLists(f)) ## Coerce tidLists to list. as(tidLists(f), "list") ## Inspect visually. image(tidLists(f))