How to remove duplicate XML nodes using PowerShell

catalog.xml

<?xml version="1.0" encoding="utf-8"?>
<CATALOG>
  <CD>
    <TITLE>Empire Burlesque</TITLE><ARTIST>Bob Dylan</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>Columbia</COMPANY><PRICE>10.90</PRICE><YEAR>1985</YEAR>
  </CD>
  <CD>
    <TITLE>Hide your heart</TITLE><ARTIST>Bonnie Tyler</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>CBS Records</COMPANY><PRICE>9.90</PRICE><YEAR>1988</YEAR>
  </CD>
  <CD>
    <TITLE>Greatest Hits</TITLE><ARTIST>Dolly Parton</ARTIST><COUNTRY>USA</COUNTRY><COMPANY>RCA</COMPANY><PRICE>9.90</PRICE><YEAR>1982</YEAR>
  </CD>
  <CD>
    <TITLE>Hide your heart</TITLE><ARTIST>Bonnie Tyler</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>CBS Records</COMPANY><PRICE>9.90</PRICE><YEAR>1988</YEAR>
  </CD>
  <CD>
    <TITLE>Hide your heart</TITLE><ARTIST>Bonnie Tyler</ARTIST><COUNTRY>UK</COUNTRY><COMPANY>CBS Records</COMPANY><PRICE>9.90</PRICE><YEAR>1988</YEAR>
  </CD>
</CATALOG>

Code:

# Load XML file

$file = "catalog.xml"
$xml = [xml](Get-Content $file)

# Add the DuppieID attribute to the XML document

$i = 1
foreach($node in $xml.CATALOG.CD)
{  
    $node.SetAttribute("DuppieID", $i)
    $i++
}

# Parse the document and delete the duplicate nodes with the exception of the first occurrence

foreach($node in $xml.CATALOG.CD)
{  
    $duplicates = ($xml.CATALOG.CD | where {$_.TITLE -eq $node.TITLE})
   
    if($duplicates.length -gt 1)
    {
        for($i = 1; $i -lt $duplicates.length; $i++)
        {
            $element = $duplicates[$i]
            $nodeToRemove = $xml.SelectSingleNode("//CATALOG/CD[@DuppieID=" + $element.DuppieID + "]")
            $nodeToRemove.ParentNode.RemoveChild($nodeToRemove)
        }
    }
}

# Remove DuppieID attribute
   
foreach($node in $xml.CATALOG.CD)
{  
    $node.RemoveAttribute("DuppieID");
}

# Update the file

$xml.Save($file)

Source: http://klemmestad.com/2014/08/08/removing-duplicate-xml-nodes-using-powershell/