Does PowerShell support constants?

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I would like to declare some integer constants in PowerShell.

Is there any good way to do that?

Use

Set-Variable test -option Constant -value 100

or

Set-Variable test -option ReadOnly -value 100

The difference between "Constant" and "ReadOnly" is that a read-only variable can be removed (and then re-created) via

Remove-Variable test -Force

whereas a constant variable can't be removed (even with -Force).

See this TechNet article for more details.

Does PowerShell support constants?, You can also create a variable and assign it a value by using the New-Variable Cmdlet. Notice that we don't use a dollar sign when we do it this  However, there’s a certain subset of PowerShell variables that can be defined but can never change. These sets are called constants and read-only variables. Constants and read-only variables are pretty much functionally equivalent. Values are assigned to a constant or read-only variable, but can never change.

Here is a solution for defining a constant like this:

const myConst = 42

Solution taken from http://poshcode.org/4063

    function Set-Constant {
  <#
    .SYNOPSIS
        Creates constants.
    .DESCRIPTION
        This function can help you to create constants so easy as it possible.
        It works as keyword 'const' as such as in C#.
    .EXAMPLE
        PS C:\> Set-Constant a = 10
        PS C:\> $a += 13

        There is a integer constant declaration, so the second line return
        error.
    .EXAMPLE
        PS C:\> const str = "this is a constant string"

        You also can use word 'const' for constant declaration. There is a
        string constant named '$str' in this example.
    .LINK
        Set-Variable
        About_Functions_Advanced_Parameters
  #>
  [CmdletBinding()]
  param(
    [Parameter(Mandatory=$true, Position=0)]
    [string][ValidateNotNullOrEmpty()]$Name,

    [Parameter(Mandatory=$true, Position=1)]
    [char][ValidateSet("=")]$Link,

    [Parameter(Mandatory=$true, Position=2)]
    [object][ValidateNotNullOrEmpty()]$Mean,

    [Parameter(Mandatory=$false)]
    [string]$Surround = "script"
  )

  Set-Variable -n $name -val $mean -opt Constant -s $surround
}

Set-Alias const Set-Constant

Read-Only and Constant Variables, But there is a built-in PowerShell cmdlet called Set-Variable that can assign variable values as well. It's not as commonly used because writing $  You can make a function read-only at anytime and delete the function using the Force parameter. You can make a function a constant, but only when the function is being created, which is identical to variables. And also like variables, you cannot remove or delete a constant function, once it’s been created.

Use -option Constant with the Set-Variable cmdlet:

Set-Variable myvar -option Constant -value 100

Now $myvar has a constant value of 100 and cannot be modified.

Constant and read-only PowerShell variables for admins who fear , Long description. You can store all types of values in PowerShell variables. The following built-in PowerShell providers support this notation:. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

To use a specific type of value, say Int64, you can explicitly cast the value used in set-variable.

For instance:

set-variable -name test -value ([int64]100) -option Constant

To check,

$test | gm

And you'll see that it is an Int64 (rather than Int32, which would be normal for the value 100).

about_Variables, New-Variable command is useful to create these variables through it's "-Option" PowerShell supports constant and read-only variables. With the release of PowerShell 7, PowerShell continues to be supported under the Microsoft Modern Lifecycle Policy , but support dates are linked to .NET Core's support lifecycle. In this servicing approach, customers can choose Long Term Support (LTS) releases or Current releases. PowerShell 7.0 is an LTS release.

PowerShell, It includes a switch that lets you define the new variable as a constant, meaning its value can't be changed. (I'll make you run. Help New-  Tech support scams are an industry-wide issue where scammers trick you into paying for unnecessary technical support services. Additionally, some scammers may try to identify themselves as a Microsoft MVP.

Q. Can I declare constants in Windows PowerShell?, Objectives and SkillsEdit. After completing this lesson, you will be able to: Explain basic concepts regarding variables. Describe the difference  Shay Levy, in http://www.powershellmagazine.com/2013/03/20/pstip-working-with-excel-constants/ has a script which demonstrates how to enumerate the constants for the Excel COM object. Get-COMConstants.ps1, is an advanced function generalization, which can be used for any COM object.

PowerShell/Variables, Summary of the new feature/enhancement This is probably going to be a matter of some debate, but I'll propose it anyway. Whenever I create a  Windows PowerShell 3.0, Windows PowerShell 4.0, and Windows PowerShell 5.0 are compiled against Common Language Runtime (CLR) 4.0. Graphical user interface requirements. Windows PowerShell is a console-based application that doesn't require a graphical user interface.

Shorthand for defining constants · Issue #8906 · PowerShell , These variables are created and maintained by Windows PowerShell. This variable is populated when you start PowerShell with the PSConsoleFile For example, the following command searches the conceptual Help topics for the word  Any Workflow Constants you do not wish to update should be removed from this file. Once you have updated the workflow constants file, save it and update the following reference in the PowerShell script (Line 71) to the location and filename chosen: Execute([Nintex.Workflow.WorkflowConstantCollection]::Deserialize([System.IO.File]::ReadAllText(" C:\export1.xml ")))

Comments
  • Hmm, but how do you force the datatype when using Set-Variable? When dealing with variables one may use [string]$name = value but that seems not to be possible for constants?
  • @masi just force the value Set-Variable test -option Constant -value [string]100
  • @Monso You need parentheses around the value when specifying type like ([string]100). See answers below.
  • Unfortunately this doesn't work when Set-Constant is contained in a module. It will create a constant in the module scope, where Set-Constant is contained. As a workaround one could pass parameter -Surround Global, but that's not always wanted. I would like to create a constant in another module or locally in a function.
  • Wow, that's clunky. You have to use Set-Variable to do it, huh?
  • Yes, there's not unclunky way to do it :)
  • you can also modify and existing variable with either set-variable (aliased to sv) or by using get-variable (gv) and tinkering with its Options property.
  • Hmm, but how do you force the datatype when using Set-Variable? When dealing with variables one may use [string]$name = value but that seems not to be possible for constants?
  • @masi - see Mike Shepard's answer elsewhere in this page. Copy and pasting from there, it's: set-variable -name test -value ([int64]100) -option Constant
  • does not work on ps 5.1. Unable to find type [static].
  • Not to mention, static is not the same as a constant