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# NumberFormatter.Behavior

These constants specify the behavior of a number formatter. These constants are returned by the [`defaultFormatterBehavior()`](/documentation/Foundation/NumberFormatter/defaultFormatterBehavior()) class method and the [`formatterBehavior`](/documentation/Foundation/NumberFormatter/formatterBehavior) property.

```
enum Behavior
```

## Topics

### Constants

[`NSNumberFormatterBehaviorDefault`](/documentation/Foundation/NumberFormatter/Behavior/default)

The number-formatter behavior set as the default for new instances. You can set the default formatter behavior with the class method [`setDefaultFormatterBehavior(_:)`](/documentation/Foundation/NumberFormatter/setDefaultFormatterBehavior(_:)).

[`NSNumberFormatterBehavior10_0`](/documentation/Foundation/NumberFormatter/Behavior/behavior10_0)

The number-formatter behavior as it existed prior to macOS 10.4.

[`NSNumberFormatterBehavior10_4`](/documentation/Foundation/NumberFormatter/Behavior/behavior10_4)

The number-formatter behavior since macOS 10.4.

## Relationships

### Conforms To

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

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

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

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

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

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

---

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