Powershell catch dynamic variable and add to array

I seek assistance in figuring out how to capture new dynamic variables and add them to an array.

Below is a sample code that creates the variables.

foreach ($user in $users) {
    New-Variable -Name "$($user)_pwString"  -Value ([System.Web.Security.Membership]::GeneratePassword(10,4)) -Force
}

This will create several variables as such:
$Guest01_pwString
$Guest02_pwString
$Guest03_pwString

How could capture each of the variables it creates and add them into an array.

What I thought would have worked:

$secureStrings = @()
foreach ($user in $users) {
    $secureStrings += (New-Variable -Name "$($user)_pwString"  -Value ([System.Web.Security.Membership]::GeneratePassword(10,4)) -Force)
}

Solution

You need the -PassThru switch in order to pass the newly created variable object through to the output stream, and you can use that object's .Value property to access the variable's value:

$secureStrings = @()
foreach ($user in $users) {
  $secureStrings += (New-Variable -PassThru -Name "$($user)_pwString"  -Value ([System.Web.Security.Membership]::GeneratePassword(10,4)) -Force).Value
}

You can streamline your command as follows:

[array] $secureStrings = 
  foreach ($user in $users) {
    (Set-Variable -PassThru -Name "${user}_pwString"  -Value ([System.Web.Security.Membership]::GeneratePassword(10, 4))).Value
  }

Taking a step back: Instead of creating individual variables, consider using an (ordered) hashtable:

$secureStrings = [ordered] @{}
foreach ($user in $users) {
  $secureStrings[$user] = [System.Web.Security.Membership]::GeneratePassword(10, 4)
}

You can then use $secureStrings.Values to extract the passwords only.