Group-Object for categorization in PowerShell

Introduction

Grouping objects helps organize data by shared properties. It makes it easier to see categories and count items in each group.

You want to count how many files have the same extension in a folder.

You need to organize a list of users by their department.

You want to group services by their status to check which are running or stopped.

You want to summarize sales data by product category.

Syntax

PowerShell

Get-Command | Group-Object -Property PropertyName

Get-Command is an example command that outputs objects.

-Property specifies the property to group by.

Examples

Groups services by their status.

PowerShell

Get-Service | Group-Object -Property Status

Groups files by their file extension.

PowerShell

Get-ChildItem | Group-Object -Property Extension

Groups a list of users by their department.

PowerShell

$users = @(
  [PSCustomObject]@{Name='Alice'; Dept='HR'},
  [PSCustomObject]@{Name='Bob'; Dept='IT'},
  [PSCustomObject]@{Name='Carol'; Dept='HR'}
)
$users | Group-Object -Property Dept

Sample Program

This script creates a list of files with extensions, groups them by extension, and prints each extension with how many files have it.

PowerShell

$files = @(
  [PSCustomObject]@{Name='file1.txt'; Extension='.txt'},
  [PSCustomObject]@{Name='file2.doc'; Extension='.doc'},
  [PSCustomObject]@{Name='file3.txt'; Extension='.txt'},
  [PSCustomObject]@{Name='file4.pdf'; Extension='.pdf'}
)

$grouped = $files | Group-Object -Property Extension

foreach ($group in $grouped) {
  Write-Output "Extension: $($group.Name) - Count: $($group.Count)"
}

Important Notes

Group-Object outputs groups with properties: Name (group key), Count (number of items), and Group (the items).

You can group by multiple properties by passing an array to -Property.

Summary

Group-Object helps organize data by shared property values.

It is useful to count or categorize items quickly.

Output groups include the group name, count, and the grouped items.