---
title: "train(trainingData:featureColumns:labelColumn:recordingFileColumn:parameters:sessionParameters:)"
framework: Create ML
role: symbol
role_heading: Type Method
platforms: [macOS 11.0+]
path: "createml/mlactivityclassifier/train(trainingdata:featurecolumns:labelcolumn:recordingfilecolumn:parameters:sessionparameters:)"
---

# train(trainingData:featureColumns:labelColumn:recordingFileColumn:parameters:sessionParameters:)

Begins an asynchronous activity classifier training session with a training dataset represented by a data source.

## Declaration

```swift
static func train(trainingData: MLActivityClassifier.DataSource, featureColumns: [String], labelColumn: String, recordingFileColumn: String, parameters: MLActivityClassifier.ModelParameters = ModelParameters(validationData: nil), sessionParameters: MLTrainingSessionParameters = _defaultSessionParameters) throws -> MLJob<MLActivityClassifier>
```

## Parameters

- `trainingData`: An doc://com.apple.createml/documentation/CreateML/MLActivityClassifier/DataSource instance.
- `featureColumns`: The names of the columns in an annotation file that contain sensor data.
- `labelColumn`: The name of the column in an annotation file that contains the activity labels if trainingData uses doc://com.apple.createml/documentation/CreateML/MLActivityClassifier/DataSource/directoryWithDataAndAnnotation(at:annotationFileName:timeStampColumn:labelStartTimeColumn:labelEndTimeColumn:). The initializer ignores this parameter if trainingData uses doc://com.apple.createml/documentation/CreateML/MLActivityClassifier/DataSource/labeledDirectories(at:).
- `recordingFileColumn`: The name of the column in an annotation file that contains the data filenames if trainingData uses doc://com.apple.createml/documentation/CreateML/MLActivityClassifier/DataSource/directoryWithDataAndAnnotation(at:annotationFileName:timeStampColumn:labelStartTimeColumn:labelEndTimeColumn:). The initializer ignores this parameter if trainingData uses doc://com.apple.createml/documentation/CreateML/MLActivityClassifier/DataSource/labeledDirectories(at:).
- `parameters`: An doc://com.apple.createml/documentation/CreateML/MLActivityClassifier/ModelParameters-swift.struct instance you use to configure the model for the training session.
- `sessionParameters`: An doc://com.apple.createml/documentation/CreateML/MLTrainingSessionParameters instance you use to configure the training session.

## Return Value

Return Value An MLJob that represents the activity classifier training session.

## See Also

### Training an activity classifier asynchronously

- [makeTrainingSession(trainingData:featureColumns:labelColumn:recordingFileColumn:parameters:sessionParameters:)](createml/mlactivityclassifier/maketrainingsession(trainingdata:featurecolumns:labelcolumn:recordingfilecolumn:parameters:sessionparameters:).md)
- [resume(_:)](createml/mlactivityclassifier/resume(_:).md)
- [restoreTrainingSession(sessionParameters:)](createml/mlactivityclassifier/restoretrainingsession(sessionparameters:).md)