Objects

PowerShell · Reference cheat sheet

📋 Overview

Almost everything in PowerShell is a .NET object with properties and methods. Pipelines pass objects; formatting is a display concern. Use Select-Object, Add-Member, and custom PSCustomObject for shaping data.

🔧 Core concepts

Common types: String, Int32, DateTime, Hashtable, Array, PSCustomObject, file/process/service objects from cmdlets.

💡 Examples

Inspect and select:

Get-ChildItem | Get-Member -MemberType Property
Get-Process |
  Select-Object Name, Id, @{N='MemMB';E={[math]::Round($_.WS/1MB,1)}}

Create objects:

$user = [pscustomobject]@{
  Name = 'Ada'
  Roles = @('admin', 'dev')
}
$user | Add-Member -NotePropertyName Active -NotePropertyValue $true

Hashtable vs object:

$map = @{ a = 1; b = 2 }          # unordered dictionary
$obj = [pscustomobject]$map       # note: key order may vary pre-PS6

Methods:

'hello'.ToUpper()
(Get-Date).AddDays(7)

⚠️ Pitfalls

• Hashtables are not PSCustomObject—property access and JSON shape differ.
• Format-Table output is not the original object—don’t pipe formats to Export-Csv.
• Value types vs references: arrays/hashtables are reference-like when passed around.
• Select-Object -ExpandProperty unwraps; without it you get objects with one property.
• Comparing objects with -eq often compares references or limited members—compare properties explicitly.
• Remote/serialized objects may be “deserialized” (methods stripped)—check Get-Member.

🔗 Related

• pipeline.md
• json_csv.md
• cmdlets.md
• variables.md
• remoting.md