Powershell reevaluate string to array

Question

i have a number of strings like this this that i would like powershell to reevaluate\convert to an array (like what would happen if you just wrote the same code in ISE without the single quotes).

$String = '@("a value","b value","c value")'

Is there a easier way to do this than stripping the '@' & '()' out of the string and using -split?

Thanks for the help in advance.

Answer 1

As long as the string contains a valid expression, you can use the [scriptblock]::Create(..) method:

$String = '@("a value","b value","c value")'
& ([scriptblock]::Create($String))

Invoke-Expression would also work but it's better to avoid it whenever possible as Ash pointed out.

---

Following zett42's nice feedback, with script block we can validate that arbitrary code execution is forbidden with CheckRestrictedLanguage.
In below example, Write-Host is an allowed command and a string containing only 'Write-Host "Hello world!"' would not throw an exception however, assignment statements or any other command not listed in $allowedCommands will throw an exception and the script block will not be executed.

$String = @'
Write-Host "Hello world!"
$stream = [System.Net.Sockets.TcpClient]::new('google.com', 80).GetStream()
'@

[string[]] $allowedCommands = 'Write-Host'
[string[]] $allowedVaribales = ''
[bool] $allowEnvVaribales = $false

try
{
    $scriptblock = [scriptblock]::Create($String)
    $scriptblock.CheckRestrictedLanguage(
        $allowedCommands, $allowedVaribales, $allowEnvVaribales
    )
    & $scriptblock
}
catch
{
    Write-Warning $_.Exception.Message
}