# subscript(_:) Reads and writes the value associated with the given key as a signed integer value. ``` subscript(key: String) -> T? where T : SignedInteger { get set } ``` ## Parameters `key` The key the look up in the dictionary. ## Return Value The value associated with key in the dictionary; otherwise, . --- 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)