Powershell: Transform object properties in the pipeline

You can use the pipeline to reduce data sets and view important information in powershell.

Take this line of vSphere PowerCLI for example:

$DStores | Select Name, FreeSpaceGB, CapacityGB

This will present some information on the datastores.

Wouldn't it be nice to be able to get the percent free on each of the datastores too? You can do this by transforming the properties using an expression as below:

$DStores | Select Name, FreeSpaceGB, CapacityGB,
        @{Name="FreePercent"; Expression={(($_.FreeSpaceGB/$_.CapacityGB)*100}} |
        Sort -Property FreePercent -Descending

This will create a new property in the pipeline called FreePercent that can be operated on in the same way as a normal property. In this example I sort using the new property.