# ..<(_:) Returns a partial range up to, but not including, its upper bound. ``` static func ..< (maximum: Self) -> PartialRangeUpTo ``` ## Parameters `maximum` The upper bound for the range. ## Discussion Use the prefix half-open range operator (prefix `..<`) to create a partial range of any type that conforms to the `Comparable` protocol. This example creates a `PartialRangeUpTo` instance that includes any value less than `5.0`. ``` let upToFive = ..<5.0 upToFive.contains(3.14) // true upToFive.contains(6.28) // false upToFive.contains(5.0) // false ``` You can use this type of partial range of a collection’s indices to represent the range from the start of the collection up to, but not including, the partial range’s upper bound. ``` let numbers = [10, 20, 30, 40, 50, 60, 70] print(numbers[..<3]) // Prints "[10, 20, 30]" ``` > Precondition: `maximum` must compare equal to itself (i.e. cannot be NaN). --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)