Compare 2 different size arrays in Powershell

Question

Hi,

I have 2 arrays which can be either in equal size or can be in different in size (size determined when the code is running). I would like to compare the text in those arrays and list down the below.

1. Output text which is present in first array but not in second array
2. Output text not in first array but is present in second array

Appreciate it if anyone could help me with the poweshell code to achieve the above.

Thanks.

Answer 1

Hi @Arosh Wijepala ,

there is a typo in your script ;-)

This is working here:

$approvedpatches = @('patch1', 'patch2', 'patch3', 'patch4', 'patch5')  
  $installedpatches = @('patch1', 'patch2', 'patch3')  
          
  $approvedpatches | ForEach-Object {  
      if ($installedpatches -notcontains $_) {  
          Write-Host "Approved but not installed [$_]"  
      }  
  }  
  $installedpatches | ForEach-Object {  
      if ($approvedpatches -notcontains $_) {  
         Write-Host "Not approved but installed [$_]"  
      }  
 }  

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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards
Andreas Baumgarten

Answer 2

Hi @Arosh Wijepala ,

maybe this helps:

# Compare 2 arrays and report which string is missing  
  
# First option  
$array1 = @('black', 'blue', 'red', 'white', 'yellow')  
$array2 = @('black', 'yellow', 'grey','purple','green')  
  
$array1 | ForEach-Object {  
    if ($array2 -notcontains $_) {  
        Write-Host "`$array2 does not contain `$array1 string [$_]"  
    }  
}  
$array2 | ForEach-Object {  
    if ($array1 -notcontains $_) {  
        Write-Host "`$array1 does not contain `$array2 string [$_]"  
    }  
}  
  
# Second option  
  
Write-Output '== means string is in both arrays  
=> missing in ReferenceObject ($array1)  
<= missing in DifferenceObject ($array2)'  
Compare-Object -ReferenceObject $array1 -DifferenceObject $array2 -IncludeEqual  

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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards
Andreas Baumgarten