7.5 Sort an Array or List of Items

Problem

You want to sort the elements of an array or list.

Solution

To sort a list of items, use the Sort-Object cmdlet:

PS > Get-ChildItem | Sort-Object -Descending Length | Select Name,Length

Name                       Length
----                       ------
Convert-TextObject.ps1       6868
Select-FilteredObject.ps1    3252
Get-PageUrls.ps1             2878
Get-Characteristics.ps1      2515
Get-Answer.ps1               1890
New-GenericObject.ps1        1490
Invoke-CmdScript.ps1         1313

Discussion

The Sort-Object cmdlet provides a convenient way for you to sort items by a property that you specify. If you don’t specify a property, the Sort-Object cmdlet follows the sorting rules of those items if they define any.

The Sort-Object cmdlet also supports custom sort expressions, rather than just sorting on existing properties. To sort by your own logic, use a script block as the sort expression. This example sorts by the second character:

PS > "Hello","World","And","PowerShell" | Sort-Object { $_.Substring(1,1) }
Hello
And
PowerShell
World

If you want to sort a list that you’ve saved in a variable, you can either store the results back in that variable or use the [Array]::Sort() method from the .NET Framework:

PS > $list = "Hello","World","And","PowerShell"
PS > $list = $list | Sort-Object
PS > $list
And
Hello
PowerShell
World
PS > $list = "Hello","World","And","PowerShell"
PS > [Array]::Sort($list)
PS > $list
And
Hello
PowerShell
World

In addition to sorting by a property or expression in ascending or descending order, the Sort-Object cmdlet’s -Unique switch also allows you to remove duplicates from the sorted collection.

For more information about the Sort-Object cmdlet, type Get-Help Sort-Object.