Compare array to add or remove item

PowerShell Help
1

I have two array which I like to compare to remove or add name to file

for example

$oldArray= @“a”, “b”, “c”

$newarray=@“a”, “b”, “d”, “e”

I would like to compare both array and add d & e but remove c because c doesnt existed in new array

$oldArray= @(“a”, “b”, “c”)
$newarray=@(“a”, “b”, “d”, “e”)

foreach ($a in $oldArray) {
if ($newarray -contains $a)
{ “Doesnt existed in new array so lets add it” }
}

 

2

I got this which is working but is it better way to do it

 

$oldArray= @(“a”, “b”, “c”)
$newarray=@(“a”, “b”, “d”, “e”)

Compare-Object -IncludeEqual -ReferenceObject $oldArray -DifferenceObject $newarray | Where-Object -FilterScript {

if($.SideIndicator -eq “=>”){Write-Host "New Object - " $.InputObject}
if($.SideIndicator -eq “<=”){Write-Host "Remove Object - " $.InputObject}

}

3

Compare being the key word, look at Compare-Object:

$oldArray= @(“a”, “b”, “c”,"f","g")
$newarray=@(“a”, “b”, “d”, “e”)

#compare the arrays, anything <= is NOT in $newArray
$compArray = Compare-Object -ReferenceObject $oldArray -DifferenceObject $newarray
#create an array of items that is NOT in $newArray
$stuffToRemove = $compArray | Where {$_.SideIndicator -eq '<='} | Select-Object -ExpandProperty InputObject
#Filter all of the $stuffToRemove from $oldArray
$oldArrayUpd = $oldArray | Where{$stuffToRemove -notcontains $_}

$oldArrayUpd

Output:

PS C:\Users\rasim> $compArray

InputObject SideIndicator
----------- -------------
d           =>           
e           =>           
c           <=           
f           <=           
g           <=           

PS C:\Users\rasim> $stuffToRemove
c
f
g

PS C:\Users\rasim> $oldArrayUpd
a
b
4

Thank you

5

And another option.

$oldArray= @(“a”, “b”, “c”)
$newarray=@(“a”, “b”, “d”, “e”)

$ItemsToAdd    = $newarray.Where({$_ -notin $oldArray})
$itemsToRemove = $oldArray.where({$_ -notin $newarray})

Output

PS C:\> $ItemsToAdd
d
e

PS C:\> $itemsToRemove
c