# PartialRangeThrough A partial interval up to, and including, an upper bound. ``` @frozen struct PartialRangeThrough where Bound : Comparable ``` ## Overview You create `PartialRangeThrough` instances by using the prefix closed range operator (prefix `...`). ``` let throughFive = ...5.0 ``` You can use a `PartialRangeThrough` instance to quickly check if a value is contained in a particular range of values. For example: ``` throughFive.contains(4.0) // true throughFive.contains(5.0) // true throughFive.contains(6.0) // false ``` You can use a `PartialRangeThrough` instance of a collection’s indices to represent the range from the start of the collection up to, and including, the partial range’s upper bound. ``` let numbers = [10, 20, 30, 40, 50, 60, 70] print(numbers[...3]) // Prints "[10, 20, 30, 40]" ``` --- 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)