[SOLVED] Powershell parse xml nodes and childnodes

Powershell parse xml nodes and childnodes

My xml is something like this

<parent>
  <somethingIamNotInterestedin>
    ....
  </somethingIamNotInterestedin>
  <body>
    <event>
      <eventid>1234</eventid>
      <list>
        <item>some text</item>
        <item>some text</item>
        <item>some text</item>
        ...many more
      </list>
      <action>DELETE</action>
    </event>
    <event>
      <eventid>3456</eventid>
      <list>
        <item>some text</item>
        <item>some text</item>
        <item>some text</item>
        ...many more
      </list>
      <action>ADD</action>
    <event>
  <body>
</parent>

I managed to count all the items in the file, but i'd like to have it grouped by event. something like (assuming i have 245 in the first list and 123 in the second)

1234;DELETE;245
3456;ADD;123

I did something like this

$events=$xml.parent.body.SelectNodes('Event')
foreach ($event in $events) { write-host $event.list.SelectNodes('item').count}

but i always get the total number.

Solution

I suggest relying exclusively on PowerShell's adaptation of the XML DOM (accessing elements as if they were properties) and using Select-Object with a calculated property to add the item count:

$xml.parent.body.event | 
  Select-Object eventid, 
                action, 
                @{ Name='count'; Expression={ $_.list.item.Count } }

Output, with your (corrected) sample data:

eventid action count
------- ------ -----
1234    DELETE     3
3456    ADD        3

The above outputs [pscustomobject] instances.

To get the exact string output as in your question, you can pipe to
ConvertTo-Csv -Delimiter ';' -NoHeader -UseQuotes AsNeeded in PowerShell (Core) 7; in Windows PowerShell, a bit more work is needed.