# TransformerToEstimatorAdaptor An estimator that always returns a predefined transformer. ``` struct TransformerToEstimatorAdaptor where Transformer : Transformer ``` ## Topics ### Creating a feature [`init(Transformer)`](/documentation/CreateMLComponents/TransformerToEstimatorAdaptor/init(_:)) Creates a trivial estimator. ### Getting the transformer [`let transformer: Transformer`](/documentation/CreateMLComponents/TransformerToEstimatorAdaptor/transformer) A pre-defined transformer. ### Encoding and Decoding [`func encode(Transformer, to: inout any EstimatorEncoder) throws`](/documentation/CreateMLComponents/TransformerToEstimatorAdaptor/encode(_:to:)) Does nothing since this estimator uses a pre-defined transformer. [`func decode(from: inout any EstimatorDecoder) throws -> Transformer`](/documentation/CreateMLComponents/TransformerToEstimatorAdaptor/decode(from:)) Returns the pre-defined transformer. ### Fitting [`func fitted(to: S, eventHandler: EventHandler?) async throws -> Transformer`](/documentation/CreateMLComponents/TransformerToEstimatorAdaptor/fitted(to:eventHandler:)) Returns the pre-defined transformer. ## Relationships ### Conforms To [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Sendable`](/documentation/Swift/Sendable) [`Estimator`](/documentation/CreateMLComponents/Estimator) --- 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)