I'm wondering how to work with nested Forach-Object, Where-Object and other Cmdlets in Powershell. For example this code:
$obj1 | Foreach-Object {
$obj2 | Where-Object { $_ .... }
}
So in the code block of Foreach-Object I use the elements of $obj1 as $_. But the same happenn in the code block of Where-Object with $obj2. So how can I access both objects elements in the Where-Object code block? I would have to do $_.Arg1 -eq $_.Arg1 but this makes no sense.
afaik, You'll need to keep a reference to the outer loop by putting it in a local variable.
$obj1 | Foreach-Object {
$myobj1 = $_
$obj2 | Where-Object { $_ .... }
}
Another way do address this is with a slighty different foreach
ForEach($item in $obj1){
$obj | Where-Object{$_.arg -eq $item.arg}
}
Still boils down to about_Scopes. $_ is always a reference to the current scope. As you must know ($_.Arg1 -eq $_.Arg1) would just be refering to itself.
$_ have a parent-object reference that can be used in these situations? Something like $itemArray | % { $_.childArray | % { $_.Parent.ParentProperty }}If the match is simple enough, you can get rid of the inner code block and avoid a local variable.
$obj1 | Foreach-Object {
$obj2 | Where property -eq $_.property
}
e.g:
$array = ("zoom", "explorer", "notreal")
$array | foreach { get-process | where ProcessName -EQ $_ | Out-Host }
You can also use scopes nowdays, e.g. a foreach inside a foreach can be accessed with $_ and the parent foreach can be accessed within the child loop using $script:_
