How can you select unique objects based on two properties of an object in powershell?

问题

I have an array of Objects that have 6 properties. That look like this:

$csvData
CURRENT DATE AND TIME : 07/10/2015 08:17:17 CST
USER NAME             : userName
COMPUTER NAME         : computerName
IP ADDRESS            : 192.168.1.1
LOGON SERVER          : logonServer
LOGON/OFF             : logon

I want to create an array of objects where username and computer name are not duplicated. How can I get only the unique username/computername combo in powershell? Ultimately I would like to remove all duplicates and add a property 'Count' that keeps track of how many duplicates there are.

I have tried:

$csvDataUnique = $csvData | Select-Object 'User Name','Computer Name' -Unique
$csvDataUnique = $csvData | sort -Property 'User Name' | Get-Unique

回答1:

Very similar to Mathias' answer, but will have all of the columns in the output:

$csvDataUnique = $csvData | 
  Group-Object 'User Name','Computer Name' | 
  %{ $_.Group | Select 'User Name','Computer Name' -First 1} | 
  Sort 'User Name','Computer Name'

回答2:

You can create a custom property with your Select-Object. So you were pretty close already. Try this:

Select-Object @{Label = "Index"; Expression = {"$($_.'User Name') $($_.'Computer Name')"} } -Unique

It basically combines the two fields into a single string and sorts unique on that. I called the field "Index" but it could be called anything.

回答3:

I usually resort to using a hash table, and joined property values for the keys for that kind of task:

$CSVDataUnique = @{}

$csvData | foreach {
 $CSVDataUnique["$_.'User Name'\$_.'Computer Name'"]++
}

回答4:

You can use Group-Object to group by multiple properties:

$Uniqs = $csvData | Group -Property "USER NAME","COMPUTER NAME" -NoElement | Select -Expand Name

回答5:

An alternative option is to use Get-Unique. It was quite helpful in my situation when I wanted to select objects based on a unique property without some extensive foreach-loop.

$csvData | Sort-Object 'User Name', 'Computer Name' | Get-Unique -AsString

The object needs to be sorted because Get-Unique compares the strings adjacent to each other. Additionally, the comparison is case-sensitive.

来源：https://stackoverflow.com/questions/31343752/how-can-you-select-unique-objects-based-on-two-properties-of-an-object-in-powers

标签

powershell

object

properties

unique