# init(_:id:children:rowContent:) Creates a hierarchical list that identifies its rows based on a key path to the identifier of the underlying data. ``` nonisolated init(_ data: Data, id: KeyPath, children: KeyPath, @ContentBuilder rowContent: @escaping (Data.Element) -> RowContent) where Content == OutlineGroup>, Data : RandomAccessCollection, ID : Hashable, RowContent : View ``` ## Parameters `data` The data for populating the list. `id` The key path to the data model’s identifier. `children` A key path to a property whose non-`nil` value gives the children of `data`. A non-`nil` but empty value denotes a node capable of having children that is currently childless, such as an empty directory in a file system. On the other hand, if the property at the key path is `nil`, then `data` is treated as a leaf node in the tree, like a regular file in a file system. `rowContent` A content builder that creates the view for a single row of the list. --- 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)