> For the complete documentation index, see [llms.txt](https://devops-collective-inc.gitbook.io/the-big-book-of-powershell-gotchas/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://devops-collective-inc.gitbook.io/the-big-book-of-powershell-gotchas/properties-vs.-values.md). # Properties vs. Values ``` $names = Get-ADComputer -filter * | Select-Object -Property Name Get-CimInstance -Class Win32_BIOS -ComputerName $names ``` Know why that won’t work? It’s because the result of Get-ADComputer is an object, which has properties. You probably knew that. But the result of Select-Object is also an object that has properties. Specifically, in this case, it’s “Selected” ADComputer object, having a single property: Name. Look at the help for Get-CimInstance. The -ComputerName parameter accepts objects of the type String. It says so, right in the help! But a Selected ADComputer object isn’t the same thing as a String. The Name property you selected contains strings, but it isn’t a string itself. This is a huge distinction, and one that trips people up all the time. Think of a property as a box. That box can contain things, but it’s a thing in and of itself, also. In this case, the box is called Name, and it contains strings. But you can’t shove that whole box into something that was just expecting strings. “Hey, I wanted a string, not a box!” Think about a fax machine. Do you remember those? They accept pages, and transmit those pages. Now suppose you have an envelope full of pages. You can’t just shove the envelope into the fax machine and expect good results. In that analogy, the envelope is a property, and the pages inside it are values. To get the pages into the fax machine, you have to take them out of the envelope first. What you want to do in this case is get the strings out of the box, and Select-Object offers a way of doing that: ``` $names = Get-ADComputer -filter * | Select-Object -ExpandProperty Name Get-CimInstance -Class Win32_BIOS -ComputerName $names ``` See the difference? -ExpandProperty gets just the contents of the specified property, rather than returning an object that only has that property. Want a simple way to test this in the shell? Run these commands: ``` Get-Service | Select -Property Name | Get-Member Get-Service | Select -ExpandProperty Name | Get-Member ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://devops-collective-inc.gitbook.io/the-big-book-of-powershell-gotchas/properties-vs.-values.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.