# Published A type that publishes a property marked with an attribute. ``` @propertyWrapper struct Published ``` ## Overview Publishing a property with the `@Published` attribute creates a publisher of this type. You access the publisher with the `$` operator, as shown here: ``` class Weather { @Published var temperature: Double init(temperature: Double) { self.temperature = temperature } } let weather = Weather(temperature: 20) cancellable = weather.$temperature .sink() { print ("Temperature now: \($0)") } weather.temperature = 25 // Prints: // Temperature now: 20.0 // Temperature now: 25.0 ``` When the property changes, publishing occurs in the property’s `willSet` block, meaning subscribers receive the new value before it’s actually set on the property. In the above example, the second time the sink executes its closure, it receives the parameter value `25`. However, if the closure evaluated `weather.temperature`, the value returned would be `20`. > Important: The `@Published` attribute is class constrained. Use it with properties of classes, not with non-class types like structures. ### See Also - [`assign(to:)`](/documentation/Combine/Publisher/assign(to:)) ## Topics ### Creating a published instance [`init(initialValue:)`](/documentation/Combine/Published/init(initialValue:)) Creates the published instance with an initial value. [`init(wrappedValue:)`](/documentation/Combine/Published/init(wrappedValue:)) Creates the published instance with an initial wrapped value. ### Publishing the value [`projectedValue`](/documentation/Combine/Published/projectedValue) The property for which this instance exposes a publisher. [`Published.Publisher`](/documentation/Combine/Published/Publisher) A publisher for properties marked with the `@Published` attribute. --- 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)