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# PreprocessingTabularEstimator

An estimator that composes a preprocessing transformer and an estimator.

```
struct PreprocessingTabularEstimator<Preprocessor, Estimator> where Preprocessor : TabularTransformer, Estimator : TabularEstimator
```

## Topics

### Creating an estimator

[`init(Preprocessor, Estimator)`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/init(_:_:))

Creates a composed estimator from a preprocessing transformer and an estimator.

### Getting the properties

[`var estimator: Estimator`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/estimator)

The estimator.

[`var preprocessor: Preprocessor`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/preprocessor)

The preprocessing transformer.

### Preprocesing and fitting

[`func preprocessed(from: DataFrame, eventHandler: EventHandler?) async throws -> DataFrame`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/preprocessed(from:eventHandler:))

Preprocesses a data frame of examples.

[`func fitted(to: DataFrame, eventHandler: EventHandler?) async throws -> PreprocessingTabularEstimator<Preprocessor, Estimator>.Transformer`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/fitted(to:eventHandler:))

Fits a composed transformer to a data frame of examples.

[`func fitted(toPreprocessed: DataFrame, eventHandler: EventHandler?) async throws -> PreprocessingTabularEstimator<Preprocessor, Estimator>.Transformer`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/fitted(toPreprocessed:eventHandler:))

Fits a transformer to a data frame of preprocessed features.

[`typealias Input`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/Input)

The input type.

[`typealias Intermediate`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/Intermediate)

The intermediate type.

[`typealias Output`](/documentation/CreateMLComponents/PreprocessingTabularEstimator/Output)

The output type.

[`protocol Transformer`](/documentation/CreateMLComponents/Transformer)

A transformer that takes an input and produces an output.

## Relationships

### Conforms To

[`TabularEstimator`](/documentation/CreateMLComponents/TabularEstimator)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Sendable`](/documentation/Swift/Sendable)

---

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