(by value: PlottableValue

, axis: Axis? = nil, span: MarkDimension = .automatic) -> some ChartContent where P : Plottable ``` ## Parameters `value` The data used for positioning marks. `axis` The axis to position marks along. Set this to `nil` to use a default configuration. `span` The span of the positioned marks. Use this to control the total amount space available to the marks. ## Discussion The code below creates a grouped bar chart that positions marks with the same “product” along the horizontal axis by their “type”. ``` Chart(cars) { BarMark( x: .value("product", $0.product), y: .value("price", $0.price) ) .position(by: .value("type", $0.type), axis: .horizontal) } ``` --- 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)