ForEach-Object for iteration in PowerShell - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the <code>ForEach-Object</code> cmdlet do in PowerShell?

It processes each item in a collection one at a time, allowing you to run a script block on each item.

beginner

How do you access the current item inside the ForEach-Object script block?

Use the automatic variable $_ to refer to the current object being processed.

beginner

Example: What will this command output?<br>

1..3 | ForEach-Object { $_ * 2 }

It outputs:<br>2<br>4<br>6<br>Each number from 1 to 3 is multiplied by 2.

intermediate

Can ForEach-Object be used to perform actions other than outputting values? Give an example.

Yes, it can run any code for each item, like writing to a file or calling a function.<br>Example:<br>

1..3 | ForEach-Object { Write-Host "Number: $_" }

intermediate

What is the difference between ForEach-Object and the foreach keyword in PowerShell?

ForEach-Object works with pipeline input and processes items one by one as they come.<br>foreach is a loop that works on a collection already in memory.<br>Use ForEach-Object for streaming data, foreach for looping over arrays.

What variable holds the current item inside a ForEach-Object script block?

A $item

B $_

C $this

D $current

The automatic variable $_ always refers to the current object in the pipeline.

Which of these commands doubles each number from 1 to 5 using ForEach-Object?

A ForEach-Object 1..5 { $_ * 2 }

B ForEach-Object { 1..5 * 2 }

C 1..5 | ForEach-Object { $_ * 2 }

D 1..5 | ForEach-Object { 2 }

Option C correctly pipes numbers 1 to 5 and multiplies each by 2 inside the script block.

What is the main use of ForEach-Object in PowerShell?

A To create functions

B To declare variables

C To stop script execution

D To process each item in a pipeline one by one

ForEach-Object is designed to handle each pipeline item individually.

Which statement is true about ForEach-Object?

A It processes items as they come through the pipeline

B It only works with arrays stored in variables

C It cannot modify items

D It is used to define functions

ForEach-Object works on streaming pipeline input, processing items one at a time.

How would you print each item from a list using ForEach-Object?

A 1..3 | ForEach-Object { Write-Host $_ }

B Write-Host 1..3

C ForEach-Object { Write-Host $_ } 1..3

D Write-Host ForEach-Object 1..3

Option A correctly pipes numbers 1 to 3 and prints each using Write-Host inside the script block.

Explain how ForEach-Object works in PowerShell and how you use it to process items.

Think about how you handle each item one by one as it flows through the pipeline.

Describe the difference between ForEach-Object and the foreach loop in PowerShell.

One works with pipeline data, the other with collections already loaded.