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# init(type:value:start:end:)

Creates a newly instantiated category sample.

```
convenience init(type: HKCategoryType, value: Int, start startDate: Date, end endDate: Date)
```

## Parameters

`type`

The category type for this sample. For a complete list, see [`HKCategoryTypeIdentifier`](/documentation/HealthKit/HKCategoryTypeIdentifier).

`value`

The value for this sample. This value must come from the appropriate category value enumeration. Each category type uses its own enumeration. For more information, see [`HKCategoryTypeIdentifier`](/documentation/HealthKit/HKCategoryTypeIdentifier).

`startDate`

The start date for the sample. This must be equal to or earlier than the end date; otherwise, this method throws an exception (<doc://com.apple.documentation/documentation/Foundation/NSExceptionName/invalidArgumentException>).

`endDate`

The end date for the sample. This must be equal to or later than the start date; otherwise, this method throws an exception (<doc://com.apple.documentation/documentation/Foundation/NSExceptionName/invalidArgumentException>).

## Return Value

A valid category sample.

## Discussion

HealthKit uses category samples to represent data that can be classified into a finite set of categories. To create a category sample, you must first create the corresponding category type, and then set its start and end dates, as shown below.

```swift
guard let categoryType =
    HKObjectType.categoryTypeForIdentifier(HKCategoryTypeIdentifierSleepAnalysis) else {
        fatalError("*** Unable to create a sleep analysis category type ***")
}
 
let categorySample = HKCategorySample(type: categoryType,
                                      value: HKCategoryValueSleepAnalysis.Asleep.rawValue,
                                      startDate: start,
                                      endDate: end)
```

## See Also

[`value`](/documentation/HealthKit/HKCategorySample/value)

The category value for this sample.

[`+  categoryTypeForIdentifier:`](/documentation/HealthKit/HKObjectType/categoryType(forIdentifier:))

Returns the shared category type for the provided identifier.

[`endDate`](/documentation/HealthKit/HKSample/endDate)

The sample’s end date.

[`categoryType`](/documentation/HealthKit/HKCategorySample/categoryType)

The category type for this sample.

[`startDate`](/documentation/HealthKit/HKSample/startDate)

The sample’s start date.


---

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