# setPreservationPriority(_:forTags:) A hint to the system of the relative order for purging tagged sets of resources in the bundle. ``` func setPreservationPriority(_ priority: Double, forTags tags: Set) ``` ## Parameters `priority` A number specifying the relative priority of preserving the resources in the group specified by `tag`. Possible values are between `0.0` and `1.0` . The default is `0.0` . The system will attempt to purge resources with lower priorities first. `tags` A set of tag names specifying resources stored in the bundle. Must not be `nil`. An exception is thrown if any of the tags in the set do not exist in your app. --- 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)