# OrdinalEncoder An ordinal encoder estimator encodes categorical values to ordinal integer values. ``` struct OrdinalEncoder where Category : Comparable, Category : Decodable, Category : Encodable, Category : Hashable ``` ## Topics ### Creating an encoder [`init()`](/documentation/CreateMLComponents/OrdinalEncoder/init()) Creates an ordinal encoding estimator. ### Fitting [`func fitted(to: S, eventHandler: EventHandler?) throws -> OrdinalEncoder.Transformer`](/documentation/CreateMLComponents/OrdinalEncoder/fitted(to:eventHandler:)) Fits an ordinal encoder to a sequence of categories. ### Default Implementations [Estimator Implementations](/documentation/CreateMLComponents/OrdinalEncoder/Estimator-Implementations) [UpdatableEstimator Implementations](/documentation/CreateMLComponents/OrdinalEncoder/UpdatableEstimator-Implementations) ## Relationships ### Conforms To [`Sendable`](/documentation/Swift/Sendable) [`Estimator`](/documentation/CreateMLComponents/Estimator) [`Copyable`](/documentation/Swift/Copyable) [`Escapable`](/documentation/Swift/Escapable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`UpdatableEstimator`](/documentation/CreateMLComponents/UpdatableEstimator) --- 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)