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# NSNumber

An object wrapper for primitive scalar numeric values.

```
class NSNumber
```

## Overview

`NSNumber` is a subclass of `NSValue` that offers a value as any C scalar (numeric) type. It defines a set of methods specifically for setting and accessing the value as a signed or unsigned `char`, `short int`, `int`, `long int`, `long long int`, `float`, or `double` or as a `BOOL`. (Note that number objects do not necessarily preserve the type they are created with.) It also defines a [`compare(_:)`](/documentation/Foundation/NSNumber/compare(_:)) method to determine the ordering of two `NSNumber` objects.

`NSNumber` is “toll-free bridged” with its Core Foundation counterparts: <doc://com.apple.documentation/documentation/CoreFoundation/CFNumber> for integer and floating point values, and <doc://com.apple.documentation/documentation/CoreFoundation/CFBoolean> for Boolean values. See [Toll-Free Bridging](https://developer.apple.com/library/archive/documentation/General/Conceptual/CocoaEncyclopedia/Toll-FreeBridgin/Toll-FreeBridgin.html#//apple_ref/doc/uid/TP40010810-CH2) for more information on toll-free bridging.

### Value Conversions

`NSNumber` provides readonly properties that return the object’s stored value converted to a particular Boolean, integer, unsigned integer, or floating point C scalar type. Because numeric types have different storage capabilities, attempting to initialize with a value of one type and access the value of another type may produce an erroneous result—for example, initializing with a `double` value exceeding `FLT_MAX` and accessing its [`floatValue`](/documentation/Foundation/NSNumber/floatValue), or initializing with an negative integer value and accessing its [`uintValue`](/documentation/Foundation/NSNumber/uintValue). In some cases, attempting to initialize with a value of a type and access the value of another type may result in loss of precision—for example, initializing with a `double` value with many significant digits and accessing its [`floatValue`](/documentation/Foundation/NSNumber/floatValue), or initializing with a large integer value and accessing its [`int8Value`](/documentation/Foundation/NSNumber/int8Value).

An `NSNumber` object initialized with a value of a particular type accessing the converted value of a different *kind* of type, such as `unsigned int` and `float`, will convert its stored value to that converted type in the following ways:

|`Value`                                                  |``doc://com.apple.foundation/documentation/Foundation/NSNumber/boolValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/intValue-95zzp``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/uintValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/floatValue``|
|---------------------------------------------------------|--------------------------------------------------------------------------|-------------------------------------------------------------------------------|--------------------------------------------------------------------------|---------------------------------------------------------------------------|
|<doc://com.apple.documentation/documentation/Swift/false>|<doc://com.apple.documentation/documentation/Swift/false>                 |`0`                                                                            |`0`                                                                       |`0.0`                                                                      |
|<doc://com.apple.documentation/documentation/Swift/true> |<doc://com.apple.documentation/documentation/Swift/true>                  |`1`                                                                            |`1`                                                                       |`1.0`                                                                      |

|`Value`|``doc://com.apple.foundation/documentation/Foundation/NSNumber/boolValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/intValue-95zzp``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/uintValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/floatValue``|
|-------|--------------------------------------------------------------------------|-------------------------------------------------------------------------------|--------------------------------------------------------------------------|---------------------------------------------------------------------------|
|`0`    |<doc://com.apple.documentation/documentation/Swift/false>                 |`0`                                                                            |`0`                                                                       |`0.0`                                                                      |
|`1`    |<doc://com.apple.documentation/documentation/Swift/true>                  |`1`                                                                            |`1`                                                                       |`1.0`                                                                      |
|`-1`   |<doc://com.apple.documentation/documentation/Swift/true>                  |`-1`                                                                           |*invalid, erroneous result*                                               |`-1.0`                                                                     |

|`Value`|``doc://com.apple.foundation/documentation/Foundation/NSNumber/boolValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/intValue-95zzp``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/uintValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/floatValue``|
|-------|--------------------------------------------------------------------------|-------------------------------------------------------------------------------|--------------------------------------------------------------------------|---------------------------------------------------------------------------|
|`0`    |<doc://com.apple.documentation/documentation/Swift/false>                 |`0`                                                                            |`0`                                                                       |`0.0`                                                                      |
|`1`    |<doc://com.apple.documentation/documentation/Swift/true>                  |`1`                                                                            |`1`                                                                       |`1.0`                                                                      |

|`Value`|``doc://com.apple.foundation/documentation/Foundation/NSNumber/boolValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/intValue-95zzp``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/uintValue``|``doc://com.apple.foundation/documentation/Foundation/NSNumber/floatValue``|
|-------|--------------------------------------------------------------------------|-------------------------------------------------------------------------------|--------------------------------------------------------------------------|---------------------------------------------------------------------------|
|`0.0`  |<doc://com.apple.documentation/documentation/Swift/false>                 |`0`                                                                            |`0`                                                                       |`0.0`                                                                      |
|`1.0`  |<doc://com.apple.documentation/documentation/Swift/true>                  |`1`                                                                            |`1`                                                                       |`1.0`                                                                      |
|`-1.0` |<doc://com.apple.documentation/documentation/Swift/true>                  |`-1`                                                                           |*invalid, erroneous result*                                               |`-1.0`                                                                     |

### Subclassing Notes

As with any class cluster, subclasses of `NSNumber` must override the primitive methods of its superclass, `NSValue`. In addition, there are two requirements around the data type your subclass represents:

1. Your implementation of [`objCType`](/documentation/Foundation/NSValue/objCType) must return one of “`c`”, “`C`”, “`s`”, “`S`”, “`i`”, “`I`”, “`l`”, “`L`”, “`q`”, “`Q`”, “`f`”, and “`d`”. This is required for the other methods of [`NSNumber`](/documentation/Foundation/NSNumber) to behave correctly.
2. Your subclass must override the accessor method that corresponds to the declared type—for example, if your implementation of [`objCType`](/documentation/Foundation/NSValue/objCType) returns  “`i`”, you must override [`int32Value`](/documentation/Foundation/NSNumber/int32Value).

## Topics

### Creating an NSNumber Object

[`numberWithBool:`](/documentation/Foundation/NSNumber/numberWithBool:)

Creates and returns an `NSNumber` object containing a given value, treating it as a `BOOL`.

[`numberWithChar:`](/documentation/Foundation/NSNumber/numberWithChar:)

Creates and returns an `NSNumber` object containing a given value, treating it as a signed `char`.

[`numberWithDouble:`](/documentation/Foundation/NSNumber/numberWithDouble:)

Creates and returns an `NSNumber` object containing a given value, treating it as a `double`.

[`numberWithFloat:`](/documentation/Foundation/NSNumber/numberWithFloat:)

Creates and returns an `NSNumber` object containing a given value, treating it as a `float`.

[`numberWithInt:`](/documentation/Foundation/NSNumber/numberWithInt:)

Creates and returns an `NSNumber` object containing a given value, treating it as a signed `int`.

[`numberWithInteger:`](/documentation/Foundation/NSNumber/numberWithInteger:)

Creates and returns an `NSNumber` object containing a given value, treating it as an `NSInteger`.

[`numberWithLong:`](/documentation/Foundation/NSNumber/numberWithLong:)

Creates and returns an `NSNumber` object containing a given value, treating it as a signed `long`.

[`numberWithLongLong:`](/documentation/Foundation/NSNumber/numberWithLongLong:)

Creates and returns an `NSNumber` object containing a given value, treating it as a signed `long long`.

[`numberWithShort:`](/documentation/Foundation/NSNumber/numberWithShort:)

Creates and returns an `NSNumber` object containing `value`, treating it as a signed `short`.

[`numberWithUnsignedChar:`](/documentation/Foundation/NSNumber/numberWithUnsignedChar:)

Creates and returns an `NSNumber` object containing a given value, treating it as an `unsigned char`.

[`numberWithUnsignedInt:`](/documentation/Foundation/NSNumber/numberWithUnsignedInt:)

Creates and returns an `NSNumber` object containing a given value, treating it as an `unsigned int`.

[`numberWithUnsignedInteger:`](/documentation/Foundation/NSNumber/numberWithUnsignedInteger:)

Creates and returns an `NSNumber` object containing a given value, treating it as an `NSUInteger`.

[`numberWithUnsignedLong:`](/documentation/Foundation/NSNumber/numberWithUnsignedLong:)

Creates and returns an `NSNumber` object containing a given value, treating it as an `unsigned long`.

[`numberWithUnsignedLongLong:`](/documentation/Foundation/NSNumber/numberWithUnsignedLongLong:)

Creates and returns an `NSNumber` object containing a given value, treating it as an `unsigned long long`.

[`numberWithUnsignedShort:`](/documentation/Foundation/NSNumber/numberWithUnsignedShort:)

Creates and returns an `NSNumber` object containing a given value, treating it as an `unsigned short`.

### Initializing an NSNumber Object

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-1ojz2)

Returns an `NSNumber` object initialized to contain a given value, treated as a `BOOL`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-8krjs)

Returns an `NSNumber` object initialized to contain a given value, treated as a signed `char`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-15chk)

Returns an `NSNumber` object initialized to contain `value`, treated as a `double`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-2vlwk)

Returns an `NSNumber` object initialized to contain a given value, treated as a `float`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-7jvmg)

Returns an `NSNumber` object initialized to contain a given value, treated as a signed `int`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-5jcjl)

Returns an `NSNumber` object initialized to contain a given value, treated as an `NSInteger`.

[`initWithLong:`](/documentation/Foundation/NSNumber/initWithLong:)

Returns an `NSNumber` object initialized to contain a given value, treated as a signed `long`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-40ad0)

Returns an `NSNumber` object initialized to contain `value`, treated as a signed `long long`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-16drx)

Returns an `NSNumber` object initialized to contain a given value, treated as a signed `short`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-8se67)

Returns an `NSNumber` object initialized to contain a given value, treated as an `unsigned char`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-47coa)

Returns an `NSNumber` object initialized to contain a given value, treated as an `unsigned int`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-3l4ek)

Returns an `NSNumber` object initialized to contain a given value, treated as an `NSUInteger`.

[`initWithUnsignedLong:`](/documentation/Foundation/NSNumber/initWithUnsignedLong:)

Returns an `NSNumber` object initialized to contain a given value, treated as an `unsigned long`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-43lc7)

Returns an `NSNumber` object initialized to contain a given value, treated as an `unsigned long long`.

[`init(value:)`](/documentation/Foundation/NSNumber/init(value:)-87y9m)

Returns an `NSNumber` object initialized to contain a given value, treated as an `unsigned short`.

### Accessing Numeric Values

[`boolValue`](/documentation/Foundation/NSNumber/boolValue)

The number object’s value expressed as a Boolean value.

[`int8Value`](/documentation/Foundation/NSNumber/int8Value)

The number object’s value expressed as a `char`.

[`decimalValue`](/documentation/Foundation/NSNumber/decimalValue)

The number object’s value expressed as an [`Decimal`](/documentation/Foundation/Decimal) structure.

[`doubleValue`](/documentation/Foundation/NSNumber/doubleValue)

The number object’s value expressed as a `double`, converted as necessary.

[`floatValue`](/documentation/Foundation/NSNumber/floatValue)

The number object’s value expressed as a `float`, converted as necessary.

[`int32Value`](/documentation/Foundation/NSNumber/int32Value)

The number object’s value expressed as an `int`, converted as necessary.

[`intValue`](/documentation/Foundation/NSNumber/intValue-95zzp)

The number object’s value expressed as an `NSInteger` object, converted as necessary.

[`int64Value`](/documentation/Foundation/NSNumber/int64Value)

The number object’s value expressed as a `long long`, converted as necessary.

[`longValue`](/documentation/Foundation/NSNumber/longValue)

The number object’s value expressed as a `long`, converted as necessary.

[`int16Value`](/documentation/Foundation/NSNumber/int16Value)

The number object’s value expressed as a `short`, converted as necessary.

[`uint8Value`](/documentation/Foundation/NSNumber/uint8Value)

The number object’s value expressed as an unsigned `char`, converted as necessary.

[`uintValue`](/documentation/Foundation/NSNumber/uintValue)

The number object’s value expressed as an `NSUInteger` object, converted as necessary.

[`uint32Value`](/documentation/Foundation/NSNumber/uint32Value)

The number object’s value expressed as an unsigned `int`, converted as necessary.

[`uint64Value`](/documentation/Foundation/NSNumber/uint64Value)

The number object’s value expressed as an unsigned `long long`, converted as necessary.

[`unsignedLongValue`](/documentation/Foundation/NSNumber/unsignedLongValue)

The number object’s value expressed as an unsigned `long`, converted as necessary.

[`uint16Value`](/documentation/Foundation/NSNumber/uint16Value)

The number object’s value expressed as an unsigned `short`, converted as necessary.

### Retrieving String Representations

[`description(withLocale:)`](/documentation/Foundation/NSNumber/description(withLocale:))

Returns a string that represents the contents of the number object for a given locale.

[`stringValue`](/documentation/Foundation/NSNumber/stringValue)

The number object’s value expressed as a human-readable string.

### Comparing NSNumber Objects

[`compare(_:)`](/documentation/Foundation/NSNumber/compare(_:))

Returns an `NSComparisonResult` value that indicates whether the number object’s value is greater than, equal to, or less than a given number.

[`isEqual(to:)`](/documentation/Foundation/NSNumber/isEqual(to:))

Returns a Boolean value that indicates whether the number object’s value and a given number are equal.

### Accessing Type Information

  <doc:nsnumber/1807278-objctype>

### Number Validation

[`NSDecimalIsNotANumber(_:)`](/documentation/Foundation/NSDecimalIsNotANumber(_:))

Returns a Boolean that indicates whether a given decimal contains a valid number.


---

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