ForEach-Object for iteration in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of ForEach-Object with simple arithmetic

What is the output of this PowerShell command?

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

PowerShell

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

A 1 2 3 4 5

B 2 4 6 8 10

C 0 2 4 6 8

D Error: Unexpected token

💡 Hint

Remember $_ represents the current item in the pipeline.

The command takes numbers 1 to 5 and multiplies each by 2, outputting 2 4 6 8 10.

💻 Command Output

intermediate

ForEach-Object with conditional output

What does this PowerShell command output?

1..4 | ForEach-Object { if ($_ % 2 -eq 0) { $_ } }

PowerShell

1..4 | ForEach-Object { if ($_ % 2 -eq 0) { $_ } }

A 1 2 3 4

B 1 3

C 2 4

D Error: Missing else block

💡 Hint

Only even numbers are output because of the condition.

The command outputs only numbers divisible by 2, which are 2 and 4.

📝 Syntax

advanced

Identify the syntax error in ForEach-Object usage

Which option contains a syntax error in using ForEach-Object?

A 1..3 | ForEach-Object Write-Output $_

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

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

D 1..3 | ForEach-Object { $_ + 1 }

💡 Hint

ForEach-Object requires a script block enclosed in braces {}.

Option A misses the braces around the script block, causing a syntax error.

🔧 Debug

advanced

Why does this ForEach-Object command output only 4 and 5?

Given this command:

1..5 | ForEach-Object { if ($_ -gt 3) { $_ } }

Why does it output only 4 and 5, but not 1, 2, 3?

PowerShell

1..5 | ForEach-Object { if ($_ -gt 3) { $_ } }

A Because the if condition filters out numbers not greater than 3

B Because ForEach-Object only processes numbers greater than 3 by default

C Because the pipeline stops after first two numbers

D Because $_ is not defined inside the script block

💡 Hint

Check the condition inside the if statement.

The if condition only outputs numbers greater than 3, so 4 and 5 are output.

🚀 Application

expert

Using ForEach-Object to modify and output a list

You have a list of filenames: 'file1.txt', 'file2.txt', 'file3.txt'.
Which command outputs the filenames without the '.txt' extension?

A @('file1.txt','file2.txt','file3.txt') | ForEach-Object { $_.Remove('.txt') }

B @('file1.txt','file2.txt','file3.txt') | ForEach-Object { $_.Replace('.txt','') }

C @('file1.txt','file2.txt','file3.txt') | ForEach-Object { $_ -replace '.txt', '' }

D @('file1.txt','file2.txt','file3.txt') | ForEach-Object { $_ -replace '\.txt$', '' }

💡 Hint

Use regex to remove only the '.txt' at the end of the string.

Option D correctly uses -replace with regex '\.txt$' to remove the extension only at the end.