Filter (xml-)Data with Where-Object on Sub-Property in PowerShell

Question

I have the following code in PowerShell:

[xml]$Xml = @"
<?xml version="1.0" encoding="utf-8"?>
<Sequences>
  <Sequence>
    <SequenceName>Sequence-A</SequenceName>
    <SequenceMeta>
      <SequenceStart>2019-07-23T17:26:54.710+02:00</SequenceStart>
      <SequenceEnd>2019-07-23T17:26:54.741+02:00</SequenceEnd>
    </SequenceMeta>
  </Sequence>
  <Sequence>
    <SequenceName>Sequence-B</SequenceName>
    <SequenceMeta>
      <SequenceStart></SequenceStart>
      <SequenceEnd></SequenceEnd>    
    </SequenceMeta>
  </Sequence>
</Sequences>
"@

Clear-Host
$Sequences = $Xml.Sequences.Sequence | Where-Object -Property SequenceMeta.SequenceEnd
$Sequences

Remove-Variable -Name Xml

As you see I load XML-Data and then I want to filter it with "Where-Object". I want to select those "Sequence(s)", where the property "SequenceEnd" has a value.

In this example, the result should be "Sequence-A". "Sequence-B" should not be shown in the results, because the "SequenceEnd"-property has no value.

I don't know how to select the sub-property "Sequence-End". I tried it like "SequenceMeta.SequenceEnd", but as you see this is not working.

I am looking for a one-liner. In reality the query will be much longer.

Thank you

AdminOfThings · Accepted Answer · 2019-07-23 16:34:28Z

You can use the following:

$Sequences = $xml.Sequences.Sequence | Where-Object {$_.SequenceMeta.SequenceEnd}
$Sequences

Since the contents within the Where-Object script block {} are a conditional expression specifically a comparison, a property with no value will yield $false and a property with a value will yield $true when no comparison operators are present. Where-Object returns all objects for which the script block statement is true.

There are some limitations with using your syntax for Where-Object, which is the comparison statement syntax. First, you can only reference the first level of properties available from the object you are piping. In other words, you can only compare SequenceMeta rather than SequenceMeta.SequenceEnd. The code $xml.Sequences.Sequence.SequenceMeta | Where-Object -Property SequenceEnd would return one object, but it would be at the SequenceMeta property level rather than its parent, which can be retrieved with the get_ParentNode method available to the XmlElement class. See below.

$Sequences = $xml.Sequences.Sequence.SequenceMeta | Where-Object -Property SequenceEnd
$Sequences.get_ParentNode()

Collectives™ on Stack Overflow

Filter (xml-)Data with Where-Object on Sub-Property in PowerShell

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related