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

# isStrictSubset(of:)

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

## Declaration

```swift
func isStrictSubset(of other: Self) -> Bool
```

## Parameters

- `other`: A set of the same type as the current 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

- [isStrictSuperset(of:)](swift/setalgebra/isstrictsuperset(of:).md)