I'm having trouble with the Compare-Object command within a function in my PowerShell script. When I run the line that sets $deletevars outside of the function, it works perfectly fine. However, inside the function, it returns nothing as if Compare-Object can't operate there. Here's a snippet of my function:
```powershell
Function clean-vars {
write-host "Sysvars = $sysvars"
$sessionvars = (get-variable).name
write-host "Sessionvars = $sessionvars"
$deletevars = compare-object -ReferenceObject $sessionvars -DifferenceObject $sysvars
write-host "Deletevars = $deletevars"
foreach ($var in $deletevars) {
if ($var.SideIndicator -eq "<=") {
Remove-Variable -Name $var.InputObject -ErrorAction SilentlyContinue
}
}
}
```
For this to work, $sysvars has to be set before running the script. I'm wondering why the Compare-Object command is not functioning as expected within the function's scope?
3 Answers
Also, remember that variables in PowerShell are scoped to the function they are defined in, unless you declare them as global. This means once the function exits, any variable created inside will no longer be accessible unless you specifically use the global scope. If you're deleting variables post-script for cleanup, consider that those variables will exit along with the function anyway unless specified otherwise.
I think I figured it out—the `-ErrorAction` was set incorrectly, which might be causing the script to skip over errors. Now, you're saying you get an error when trying to remove a variable that indeed exists. You should make sure that the scope of your variables is correct. Try running this part of your code in the same script block instead of relying on the function, as functions use their own variable scope.
Good call! If you're trying to manage the variable directly without scoping issues, keeping everything in one block should help resolve those errors you're facing.
It looks like the issue is that the variable `$sysvars` isn't defined within the scope of your function. When you try to use Compare-Object, it doesn't have anything to compare `$sessionvars` against, which leads to it returning nothing. You might want to pass `$sysvars` as a parameter to your function so it's accessible within its scope, or define it within the function itself.
Right! Passing it as a parameter could really streamline things. Just be cautious of variable scope in PowerShell; they can get tricky inside functions.
Exactly! This is especially handy when debugging, but if the variable management gets too cumbersome, it might indicate a need for a script refactor. Just restarting the terminal can also work, but it sounds like you're looking for a cleaner method.