Instance Method

# isStrictSubset(of:)

Returns a Boolean value that indicates whether this set is a strict subset of the given set.

## Parameters

`other`

A set of the same type as the current set.

## Return Value

`true` if the set is a strict subset of `other`; otherwise, `false`.

## Discussion

Set A is a strict subset of another set B if every member of A is also a member of B and B contains at least one element that is not a member of A.

### Testing Set Membership

`func contains(IndexSet.Element) -> Bool`

Returns `true` if `self` contains `integer`.

`func contains(integersIn: IndexSet) -> Bool`

Returns `true` if `self` contains all of the integers in `indexSet`.

`func contains(integersIn: Range<IndexSet.Element>) -> Bool`

Returns `true` if `self` contains all of the integers in `range`.

`func contains(where: (Int) -> Bool) -> Bool`

Returns a Boolean value indicating whether the sequence contains an element that satisfies the given predicate.

`func intersects(integersIn: Range<IndexSet.Element>) -> Bool`

Returns `true` if `self` intersects any of the integers in `range`.

`func starts<PossiblePrefix>(with: PossiblePrefix) -> Bool`

Returns a Boolean value indicating whether the initial elements of the sequence are the same as the elements in another sequence.

`func isDisjoint(with: IndexSet) -> Bool`

Returns a Boolean value that indicates whether the set has no members in common with the given set.

`func isStrictSuperset(of: IndexSet) -> Bool`

Returns a Boolean value that indicates whether this set is a strict superset of the given set.

`func isSubset(of: IndexSet) -> Bool`

Returns a Boolean value that indicates whether the set is a subset of another set.

`func isSuperset(of: IndexSet) -> Bool`

Returns a Boolean value that indicates whether the set is a superset of the given set.