# value(atY:as:) Returns the data value at the given y position, or `nil` if the position does not correspond to a valid Y value. ``` func value

(atY position: CGFloat, as: P.Type = P.self) -> P? where P : Plottable ``` ## Parameters `position` The position at which to obtain the y data value. It should be relative to the plot. ## Return Value The data value at the given position. --- 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)