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# NSWhoseSpecifier.SubelementIdentifier

`NSWhoseSpecifier` uses these constants to specify sub-elements within the collection of objects being tested that pass the specifier’s test.

```
enum SubelementIdentifier
```

## Overview

These constants are used by [`startSubelementIdentifier`](/documentation/Foundation/NSWhoseSpecifier/startSubelementIdentifier), [`startSubelementIdentifier`](/documentation/Foundation/NSWhoseSpecifier/startSubelementIdentifier), [`endSubelementIdentifier`](/documentation/Foundation/NSWhoseSpecifier/endSubelementIdentifier), and [`endSubelementIdentifier`](/documentation/Foundation/NSWhoseSpecifier/endSubelementIdentifier).

## Topics

### Constants

[`NSIndexSubelement`](/documentation/Foundation/NSWhoseSpecifier/SubelementIdentifier/indexSubelement)

An element at a given index that meets the specifier test.

[`NSEverySubelement`](/documentation/Foundation/NSWhoseSpecifier/SubelementIdentifier/everySubelement)

Every element that meets the specifier test.

[`NSMiddleSubelement`](/documentation/Foundation/NSWhoseSpecifier/SubelementIdentifier/middleSubelement)

The middle element that meets the specifier test.

[`NSRandomSubelement`](/documentation/Foundation/NSWhoseSpecifier/SubelementIdentifier/randomSubelement)

Any element that meets the specifier test.

[`NSNoSubelement`](/documentation/Foundation/NSWhoseSpecifier/SubelementIdentifier/noSubelement)

No sub-element met the specifier test. Valid only for specifying the end sub-element.; that is, there is no end, so consider all elements.

## Relationships

### Conforms To

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

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

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

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

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

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

---

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