---
title: "isStrictSubset(of:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/set/isstrictsubset(of:)-96vc3"
---

# isStrictSubset(of:)

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

## Declaration

```swift
func isStrictSubset(of other: Set<Element>) -> Bool
```

## Parameters

- `other`: Another set.

## Return Value

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

## Discussion

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. let employees: Set = ["Alicia", "Bethany", "Chris", "Diana", "Eric"] let attendees: Set = ["Alicia", "Bethany", "Diana"] print(attendees.isStrictSubset(of: employees)) // Prints "true"

// A set is never a strict subset of itself: print(attendees.isStrictSubset(of: attendees)) // Prints "false"

## See Also

### Comparing Sets

- [==(_:_:)](swift/set/==(_:_:).md)
- [!=(_:_:)](swift/set/!=(_:_:).md)
- [isSubset(of:)](swift/set/issubset(of:)-1d7pp.md)
- [isSubset(of:)](swift/set/issubset(of:)-6qyo5.md)
- [isStrictSubset(of:)](swift/set/isstrictsubset(of:)-787sx.md)
- [isSuperset(of:)](swift/set/issuperset(of:)-9iz62.md)
- [isSuperset(of:)](swift/set/issuperset(of:)-90hri.md)
- [isStrictSuperset(of:)](swift/set/isstrictsuperset(of:)-4d27m.md)
- [isStrictSuperset(of:)](swift/set/isstrictsuperset(of:)-58ejg.md)
- [isDisjoint(with:)](swift/set/isdisjoint(with:)-8ngmk.md)
- [isDisjoint(with:)](swift/set/isdisjoint(with:)-2onid.md)