about_Ref - PowerShell command help and examples

Describes how to create and use a reference variable type. (about_Ref)

Describes how to create and use a reference variable type.
You can use the reference variable type to permit a method to change the value of a variable that is passed to it. When the [ref] type is associated with an object, it returns a reference to that object. If the reference is used with a method, the method can refer to the object that was passed to it. If the object is changed within the method, the change appears as a change in the value of the variable when control returns to the calling method. To use referencing, the parameter must be a reference variable. If it is not, an InvalidArgument exception is thrown. The parameters used in method invocations must match the type required by the methods. Examples: PS> function swap([ref]$a,[ref]$b) >> { >> $a.value,$b.value = $b.value,$a.value >> } PS> $a = 1 PS> $b = 10 PS> $a,$b 1 10 PS> swap ([ref]$a) ([ref]$b) PS> $a,$b 10 1 PS C:\ps-test> function double >> { >> param ([ref]$x) $x.value = $x.value * 2 >> } PS C:> $number = 8 PS C:> $number 8 PS C> double ([ref]$number) PS C> $number 16 The variable must be a reference variable. PS C:\ps-test> double $number double : Reference type is expected in argument. At line:1 char:7 + double <<<< $number SEE ALSO about_Variables about_Environment_Variables about_Functions about_Script_Blocks C:\Windows>powershell get-help about_regular_expressions -full

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PowerShell: Describes how to create and use a reference variable type.

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