How to modify parent scope variable using Powershell

Question

I'm fairly new to powershell, and I'm just not getting how to modify a variable in a parent scope:

$val = 0 function foo() {     $val = 10 } foo write "The number is: $val" 

When I run it I get:

The number is: 0 

I would like it to be 10. But powershell is creating a new variable that hides the one in the parent scope.

I've tried these, with no success (as per the documentation):

$script:$val = 10 $global:$val = 10 $script:$val = 10 

But these don't even 'compile' so to speak. What am I missing?

Answer 1

You don't need to use the global scope. A variable with the same name could have been already exist in the shell console and you may update it instead. Use the script scope modifier. When using a scope modifier you don't include the $ sign in the variable name.

$script:val=10

Answer 2

I know this is crazy old but I had a similar question and found this post in my search and wanted to share the answer I found:

$val = 0 function foo {     Set-Variable -scope 1 -Name "Val" -Value "10" } foo write "The number is: $val" 

More information can be found in the Microsoft Docs article About Scopes.

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Be aware that recursive functions require the scope to be adjusted accordingly:

$val = ,0 function foo {     $b = $val.Count     Set-Variable -Name 'val' -Value ($val + ,$b) -Scope $b     if ($b -lt 10) {         foo     } }