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 dgCMatrix
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
:dgCMatrix
.itemInfo
:"data.frame"
always an
empty data.frame for transaction ID lists.transactionInfo
:"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 = "dgCMatrix")
;
access the sparse matrix representation. In the
dgCMatrix
each column represents the transaction IDs
for one item/itemset.signature(from = "tidLists", to = "list")
signature(from = "tidLists", to = "matrix")
signature(from = "tidLists", to = "dgCMatrix")
signature(from = "tidLists", to = "itemMatrix")
signature(from = "itemMatrix", to = "tidLists")
signature(from = "tidLists", to = "transactions")
signature(from = "transactions", to = "tidLists")
signature(x = "tidLists")
;
returns the dimensions of the sparse Matrix representing the
tidLists
.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
.itemInfo
.signature(object = "tidLists")
;
returns the item labels as a character vector.signature(x = "transactions")
:
returns the slot transactionInfo
.signature(object = "tidLists")
signature(object = "tidLists")
[-methods
,
LIST
,
eclat
,
image
,
length
,
size
,
dgCMatrix
(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")