---
title: "fitted(to:validateOn:eventHandler:)"
framework: createmlcomponents
role: symbol
role_heading: Instance Method
path: "createmlcomponents/annotatedfeatureprovider/fitted(to:validateon:eventhandler:)"
---

# fitted(to:validateOn:eventHandler:)

Fits a transformer to a data frame

## Declaration

```swift
func fitted(to input: DataFrame, validateOn validation: DataFrame? = nil, eventHandler: EventHandler? = nil) async throws -> ColumnSelectorTransformer<Base.Transformer, UnwrappedInput>
```

## Parameters

- `input`: A data frame containing examples used for fitting the transformer.
- `validation`: A data frame containing examples used for validating the fitted transformer.
- `eventHandler`: An event handler.

## Return Value

Return Value The fitted transformer.

## See Also

### Fitting

- [AnnotatedFeatureProvider.Transformer](createmlcomponents/annotatedfeatureprovider/transformer.md)