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about_Numeric_Literals

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Short description

This article describes the syntax and usage of numeric values in PowerShell.

Long description

There are two kinds of numeric literals: integer and real. Both can have type and multiplier suffixes.

Integer literals

Integer literals can be written in decimal or hexadecimal notation. Hexadecimal literals are prefixed with 0x to distinguish them from decimal numbers.

Integer literals can have a type suffix and a multiplier suffix.

Suffix Meaning
l long data type
kb kibibyte (10241) multiplier
mb mebibyte (10242) multiplier
gb gigibyte (10243) multiplier
tb teribyte (10244) multiplier
pb petibyte (10245) multiplier

The type of an integer literal is determined by its value, the type suffix, and the numeric multiplier suffix.

For an integer literal with no type suffix:

  • If the value can be represented by type [int], that is its type.
  • Otherwise, if the value can be represented by type [long], that is its type.
  • Otherwise, if the value can be represented by type [decimal], that is its type.
  • Otherwise, it is represented by type [double].

For an integer literal with a type suffix:

  • If the type suffix is u and the value can be represented by type [int] then its type is [int].
  • If the type suffix is u and the value can be represented by type [long] then its type is [long].
  • If its value can be represented by type specified then that is its type.
  • Otherwise, that literal is malformed.

Real literals

Real literals can only be written in decimal notation. This notation can include fractional values following a decimal point and scientific notation using an exponential part.

The exponential part includes an 'e' followed by an optional sign (+/-) and a number representing the exponent. For example, the literal value 1e2 equals the numeric value 100.

Real literals can have a type suffix and a multiplier suffix.

Suffix Meaning
d decimal data type
kb kibibyte (10241) multiplier
mb mebibyte (10242) multiplier
gb gigibyte (10243) multiplier
tb teribyte (10244) multiplier
pb petibyte (10245) multiplier

There are two kinds of real literal: double and decimal. These are indicated by the absence or presence, respectively, of decimal-type suffix. PowerShell does not support a literal representation of a [float] value. A double real literal has type [double]. A decimal real literal has type [decimal]. Trailing zeros in the fraction part of a decimal real literal are significant.

If the value of exponent-part's digits in a [double] real literal is less than the minimum supported, the value of that [double] real literal is 0. If the value of exponent-part's digits in a [decimal] real literal is less than the minimum supported, that literal is malformed. If the value of exponent-part's digits in a [double] or [decimal] real literal is greater than the maximum supported, that literal is malformed.

Note

The syntax permits a double real literal to have a long-type suffix. PowerShell treats this case as an integer literal whose value is represented by type [long]. This feature has been retained for backwards compatibility with earlier versions of PowerShell. However, programmers are discouraged from using integer literals of this form as they can easily obscure the literal's actual value. For example, 1.2L has value 1, 1.2345e1L has value 12, and 1.2345e-5L has value 0, none of which are immediately obvious.

Numeric multipliers

For convenience, integer and real literals can contain a numeric multiplier, which indicates one of a set of commonly used powers of 2. The numeric multiplier can be written in any combination of upper or lowercase letters.

The multiplier suffixes can be used in combination with the u, ul, and l type suffixes.

Multiplier examples

PS> 1kb
1024

PS> 1.30Dmb
1363148.80

PS> 0x10Gb
17179869184

PS> 1.4e23tb
1.5393162788864E+35

PS> 0x12Lpb
20266198323167232

Numeric type accelerators

PowerShell supports the following type accelerators:

Accelerator Note Description
[byte] Byte (unsigned)
[sbyte] Byte (signed)
[Int16] 16-bit integer
[UInt16] 16-bit integer (unsigned)
[Int32] 32-bit integer
[int] alias for [int32] 32-bit integer
[UInt32] 32-bit integer (unsigned)
[Int64] 64-bit integer
[long] alias for [int64] 64-bit integer
[UInt64] 64-bit integer (unsigned)
[bigint] See BigInteger Struct
[single] Single precision floating point
[float] alias for [single] Single precision floating point
[double] Double precision floating point
[decimal] 128-bit floating point

Working with other numeric types

To work with any other numeric types you must use type accelerators, which is not without some problems. For example, high integer values are always parsed as double before being cast to any other type.

PS> [bigint]111111111111111111111111111111111111111111111111111111
111111111111111100905595216014112456735339620444667904

The value is parsed as a double first, losing precision in the higher ranges. To avoid this problem, enter values as strings and then convert them:

PS> [bigint]'111111111111111111111111111111111111111111111111111111'
111111111111111111111111111111111111111111111111111111

Examples

The following table contains several examples of numeric literals and lists their type and value:

Number Type Value
100 Int32 100
100D Decimal 100
100l Int64 100
1e2 Double 100
1.e2 Double 100
0x1e2 Int32 482
0x1e2L Int64 482
0x1e2D Int32 7725
482D Decimal 482
482gb Int64 517543559168
0x1e2lgb Int64 517543559168

Numeric type conversion

When strings are converted to numbers, additional hexadecimal format indicators are supported. Those additional formats are not recognized as literals.

[int] '0xF' -eq 0xF
[int] '&hF' -eq 0xF
[int] '#F' -eq 0xF

Commands that look like numeric literals

Any command that looks like a numeric literal must be executed using the call operator (&), otherwise it is interpreted as a number of the associated type.

Access properties and methods of numeric objects

To access a member of a numeric literal, there are cases when you need to enclose the literal in parentheses.

  • The literal does not have a decimal point
  • The literal does not have any digits following the decimal point
  • The literal does not have a suffix

For example, the following example fails:

PS> 2.GetType().Name
At line:1 char:11
+ 2.GetType().Name
+           ~
An expression was expected after '('.
+ CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
+ FullyQualifiedErrorId : ExpectedExpression

The following examples work:

PS> 2L.GetType().Name
Int64
PS> 1.234.GetType().Name
Double
PS> (2).GetType().Name
Int32

The first two examples work without enclosing the literal value in parentheses because the PowerShell parser can determine where the numeric literal ends and the GetType method starts.