A few weeks ago my friend, Gladys Kravitz, was lamenting about a challenge related to filtering for unique objects. PowerShell has a Get-Unique cmdlet, and Select-Object has a -Unique parameter, but these options are limited. On one hand, I’d say most things we manage with PowerShell are guaranteed to be unique. Objects might have a GUID , ID, or SID, to guarantee uniqueness. But, and this is Gladys’ situation, sometimes the things we are managing come from an external source. Such as importing data from a CSV file. In this situation, it is definitely possible to have duplicate objects.
This turns out to be a bit harder than expected.