Accessing variables created inside a function after the function has executed

Question

I'm using a function which creates some variables I'd like to use after the function has processed. I've tried accessing them directly but I can't. How would I go about doing this?

Answer 1

Variables inside functions don't survive after the function has been run. If you want to access them after the function has processed, prefix them with a scope modifier.

PS> function test-var{ $script:var='foo' }
PS> test-var # excute the function
PS> $var #print var
foo

Type this in your console for more information:

PS> Get-Help about_Scopes

Answer 2

as Shay pointed out you can create what are called global variables inside the function scope that will be available at higher level scopes. However global variables are generally not a good idea and I'd like to suggest some alternatives for you.

This is from the wikipedia global variable page:

They are usually considered bad practice precisely because of their non-locality: a global variable can potentially be modified from anywhere (unless they reside in protected memory or are otherwise rendered read-only), and any part of the program may depend on it.[1] A global variable therefore has an unlimited potential for creating mutual dependencies, and adding mutual dependencies increases complexity.

Some alternatives:

• Make the function return data needed by the caller. Powershell functions should generally return the data related to the noun in the Powershell function naming convention of Verb-Noun. If you need to return other data not associated to the noun consider making a second function.

  function Get-Directories {
      param ([string] $Path)
  
      # Code to get or create objects here.
      $dirs = Get-ChildItem -Path $Path | where {$_.PsIsContainer}
  
      # Explicitly return data to the caller.
      return $dirs
  }
  
  $myDirs = Get-Directories -Path 'C:\'
  

• Use a reference variable. A reference passes a variable's address in memory to a function. When the function changes the variable's data it will be accessible outside of the function but the variable's scope will not of been changed.

  function Get-Directories {
      param ([string] $Path, [ref] $Directories)
      $Directories.Value = Get-ChildItem -Path $Path | where {$_.PsIsContainer}
  }
  
  $myDirs = $null
  Get-Directories -Path 'C:\' -Directories ([ref] $myDirs)
  

Hope this helps. Happy coding :-)