The scenario: I'm using Select-Object to access properties of a piped object, and one of those properties is itself an object. Let's call it PropertyObject. I want to access a property of that PropertyObject, say Property1. Is there any nice and clean way of accessing Property1, along the lines of:
...| select-object PropertyObject.Property1
While experimenting I can only get it to work if I do something like:
...| select-object {$_.PropertyObject.Property1}
and if I want to display it with a decent column name it gets even messier:
...| select-object @{Name="Property1"; Expression={$_.PropertyObject.Property1}}
Given how clean and concise PowerShell is in general, I can't help thinking I'm missing something and there should be a cleaner way of accessing a property of a property. Is there?
EDIT: As requested by Matt, here is the concrete example:
I'm reading an XML file, Books3.xml:
<?xml version="1.0"?>
<catalog>
<book id="bk101">
<author>Gambardella, Matthew</author>
<title>XML Developer's Guide</title>
<genre>Computer</genre>
<price>44.95</price>
<publish_date inprint="false">2000-10-01</publish_date>
<description>An in-depth look at creating applications
with XML.</description>
<publisher>
<name>Simon and Schuster</name>
<country>USA</country>
<city>New York</city>
</publisher>
</book>
<book id="bk102">
<author>Ralls, Kim</author>
<title>Midnight Rain</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date inprint="true">2000-12-16</publish_date>
<description>A former architect battles corporate zombies,
an evil sorceress, and her own childhood to become queen
of the world.</description>
<publisher>
<name>HarperCollins</name>
<country>USA</country>
<city>New York</city>
</publisher>
</book>
<book id="bk103">
<author>Corets, Eva</author>
<title>Maeve Ascendant</title>
<genre>Fantasy</genre>
<price>5.95</price>
<publish_date inprint="false">2000-11-17</publish_date>
<description>After the collapse of a nanotechnology
society in England, the young survivors lay the
foundation for a new society.</description>
<publisher>
<name>Macmillan</name>
<country>United Kingdom</country>
<city>London</city>
</publisher>
</book>
</catalog>
Code to load XML into XmlDocument:
$filePath = "C:\Temp\books3.xml"
$xmlDoc = new-object xml
$xmlDoc.load($filePath)
Attempting to read details for each book:
$xmlDoc.catalog.book | select author, title, publisher.name
Result:
author title publisher.name
------ ----- --------------
Gambardella, Matthew XML Developer's Guide
Ralls, Kim Midnight Rain
Corets, Eva Maeve Ascendant
Object properties To get the properties of an object, use the Get-Member cmdlet. For example, to get the properties of a FileInfo object, use the Get-ChildItem cmdlet to get the FileInfo object that represents a file.
Description. The Select-Object cmdlet selects specified properties of an object or set of objects. It can also select unique objects, a specified number of objects, or objects in a specified position in an array. To select objects from a collection, use the First, Last, Unique, Skip, and Index parameters.
With the help of the Select-Object cmdlet, you can add a calculated property to the output of a PowerShell command. This allows you to enrich the displayed information.
You can use calculated properties. A short form would allow for this:
$xmlDoc.catalog.book | select author, title, {$_.publisher.name}
If the property names are important you need to add them in.
$xmlDoc.catalog.book | select author, title, @{N="PublisherName";E={$_.publisher.name}}
Where N is short for name and E is short for expression.
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