---
title: "init(_:id:content:)"
framework: swiftui
role: symbol
role_heading: Initializer
path: "swiftui/slidertickcontentforeach/init(_:id:content:)"
---

# init(_:id:content:)

Creates an instance that uniquely identifies and creates slider ticks across updates based on the provided key path to the underlying data’s identifier.

## Declaration

```swift
nonisolated init<V>(_ data: Data, id: KeyPath<Data.Element, ID>, @SliderTickBuilder<V> content: @escaping (Data.Element) -> Content) where V == Data.Element, Data.Element == Content.Value
```

## Parameters

- `data`: The data that the doc://com.apple.SwiftUI/documentation/SwiftUI/ForEach instance uses to create mark items dynamically.
- `id`: The key path to the provided data’s identifier.
- `content`: The builder that creates ticks dynamically.

## Discussion

Discussion It’s important that the id of a data element doesn’t change, unless SwiftUI considers the data element to have been replaced with a new data element that has a new identity. If the id of a data element changes, then the marks generated from that data element will lose any current state and animations.