# is.superset

##### Find Super and Subsets

Provides the generic functions and the S4 methods `is.subset`

and
`is.superset`

for finding super or subsets in associations and
itemMatrix objects.

- Keywords
- manip

##### Usage

```
is.subset(x, y = NULL, proper = FALSE, sparse = TRUE, ...)
is.superset(x, y = NULL, proper = FALSE, sparse = TRUE, ...)
```

##### Arguments

- x, y
associations or itemMatrix objects. If

`y = NULL`

, the super or subset structure within set`x`

is calculated.- proper
a logical indicating if all or just proper super or subsets.

- sparse
a logical indicating if a sparse (ngCMatrix) rather than a dense logical matrix sgould be returned. Sparse computation preserves a significant amount of memory and is much faster for large sets.

- …
currently unused.

##### Details

looks for each element in `x`

which elements in `y`

are supersets or
subsets. Note that the method can be very slow and memory intensive if
`x`

and/or `y`

contain many elements.

For rules, the union of lhs and rhs is used a the set of items.

##### Value

returns a logical matrix
or a sparse ngCMatrix (for `sparse=TRUE`

)
with `length(x)`

rows and `length(y)`

columns. Each logical row vector represents which elements in `y`

are
supersets (subsets) of the corresponding element in `x`

. If either
`x`

or `y`

have length zero, `NULL`

is returned instead of a
matrix.

##### See Also

##### Examples

```
# NOT RUN {
data("Adult")
set <- eclat(Adult, parameter = list(supp = 0.8))
### find the supersets of each itemset in set
is.superset(set, set)
is.superset(set, set, sparse = FALSE)
# }
```

*Documentation reproduced from package arules, version 1.5-4, License: GPL-3*