ForEach loop in PowerShell - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to loop through each item in the array and print it.

PowerShell

foreach ($item [1] $array) { Write-Output $item }

Drag options to blanks, or click blank then click option'

Aof

Bon

Cin

Dat

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'of' or 'on' instead of 'in' causes syntax errors.

Leaving out the keyword entirely.

The keyword in is used in PowerShell to loop through each element in a collection.

2fill in blank

medium

Complete the code to loop through numbers 1 to 5 and print each number.

PowerShell

foreach ($num [1] 1..5) { Write-Output $num }

Drag options to blanks, or click blank then click option'

Ain

Bfrom

Con

Dof

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'from' or 'of' instead of 'in' causes errors.

Trying to use a comma-separated list without the range operator.

Use in to loop through a range of numbers in PowerShell.

3fill in blank

hard

Fix the error in the loop to correctly print each name in the list.

PowerShell

$names = @('Anna', 'Bob', 'Cara')
foreach ($name [1] $names) { Write-Output $name }

Drag options to blanks, or click blank then click option'

Ain

Bon

Cat

Dof

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'on' or 'of' causes the loop to fail.

Forgetting the keyword entirely.

The correct keyword to iterate over a collection in PowerShell is in.

4fill in blank

hard

Fill both blanks to create a loop that prints only even numbers from 1 to 10.

PowerShell

foreach ($num [1] 1..10) { if ($num [2] 2 -eq 0) { Write-Output $num } }

Drag options to blanks, or click blank then click option'

Ain

B%

C==

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '%' for checking even numbers.

Using 'on' instead of 'in' for the loop.

Use in to loop through the numbers and % (modulus) to check if the number is even.

5fill in blank

hard

Fill all three blanks to create a dictionary of word lengths for words longer than 3 characters.

PowerShell

$words = @('cat', 'house', 'tree', 'a', 'dog')
$lengths = @{}
foreach ($word [1] $words) { if ($word.Length [2] 3) { $lengths[[3]] = $word.Length } }
$lengths

Drag options to blanks, or click blank then click option'

Ain

B>

C$word

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' for length comparison.

Using the wrong key for the dictionary.

Use in to loop through words, > to check length greater than 3, and $word as the dictionary key.

Practice

1. What does the foreach loop do in PowerShell?

easy

A. Creates a new collection from scratch

B. Runs code only once regardless of the collection

C. Repeats a block of code for each item in a collection

D. Stops the script immediately

Solution

1. Step 1: Understand the foreach loop purpose

   The foreach loop is designed to repeat actions for every item in a list or collection.

2. Step 2: Compare options to this purpose

   Only Repeats a block of code for each item in a collection correctly describes repeating code for each item in a collection.

3. Final Answer:

   Repeats a block of code for each item in a collection -> Option C

4. Quick Check:

   foreach = repeat for each item [OK]

Hint: Think: foreach means 'for each item' repeat [OK]

Common Mistakes:

• Confusing foreach with a one-time action
• Thinking foreach creates new collections
• Believing foreach stops the script

2. Which of the following is the correct syntax for a foreach loop in PowerShell?

easy

A. foreach ($item in $list) { Write-Output $item }

B. foreach $item in $list { Write-Output $item }

C. foreach ($item : $list) { Write-Output $item }

D. foreach ($item; $list) { Write-Output $item }

Solution

1. Step 1: Recall correct foreach syntax

   PowerShell foreach loops use: foreach ($var in $collection) { ... }

2. Step 2: Match options to syntax

   Only foreach ($item in $list) { Write-Output $item } uses the correct 'in' keyword and parentheses.

3. Final Answer:

   foreach ($item in $list) { Write-Output $item } -> Option A

4. Quick Check:

   Syntax uses 'in' keyword inside parentheses [OK]

Hint: Look for 'foreach ($var in $collection)' pattern [OK]

Common Mistakes:

• Omitting parentheses around variable and collection
• Using ':' or ';' instead of 'in'
• Missing the 'in' keyword

3. What will be the output of this PowerShell script?

foreach ($num in 1..3) { Write-Output ($num * 2) }

medium

A. 2 4 6

B. 1 2 3

C. 3 6 9

D. Error: Invalid syntax

Solution

1. Step 1: Understand the loop range

   The loop runs for numbers 1, 2, and 3.

2. Step 2: Calculate output for each iteration

   Each number is multiplied by 2, so outputs are 2, 4, and 6.

3. Final Answer:

   2 4 6 -> Option A

4. Quick Check:

   1*2=2, 2*2=4, 3*2=6 [OK]

Hint: Multiply each loop number by 2 mentally [OK]

Common Mistakes:

• Confusing the range operator '..'
• Thinking output is original numbers
• Expecting syntax error

4. Identify the error in this PowerShell foreach loop:

foreach $item in $array { Write-Output $item }

medium

A. No error, code is correct

B. Missing parentheses around the loop variable and collection

C. Using $item instead of $i as loop variable

D. Incorrect use of Write-Output

Solution

1. Step 1: Check foreach syntax

   PowerShell requires parentheses around the variable and collection in foreach loops.

2. Step 2: Identify missing parentheses

   The code lacks parentheses: it should be foreach ($item in $array) { ... }

3. Final Answer:

   Missing parentheses around the loop variable and collection -> Option B

4. Quick Check:

   foreach needs parentheses [OK]

Hint: Always use parentheses in foreach syntax [OK]

Common Mistakes:

• Omitting parentheses
• Confusing variable names
• Thinking Write-Output causes error

5. You have a list of filenames stored in $files. You want to print only those filenames that end with '.txt' using a foreach loop. Which script correctly does this?

hard

A. foreach ($file in $files) { if ($file -eq '*.txt') { Write-Output $file } }

B. foreach ($file in $files) { if ($file contains '.txt') { Write-Output $file } }

C. foreach ($file in $files) { Write-Output $file -match '.txt' }

D. foreach ($file in $files) { if ($file -like '*.txt') { Write-Output $file } }

Solution

1. Step 1: Understand filtering condition

   To check if a filename ends with '.txt', use the '-like' operator with '*.txt' pattern.

2. Step 2: Verify foreach loop and condition

   foreach ($file in $files) { if ($file -like '*.txt') { Write-Output $file } } correctly uses foreach with an if condition checking '-like "*.txt"' and outputs matching files.

3. Final Answer:

   foreach ($file in $files) { if ($file -like '*.txt') { Write-Output $file } } -> Option D

4. Quick Check:

   Use '-like' with wildcard for pattern match [OK]

Hint: Use '-like "*.txt"' inside if in foreach [OK]

Common Mistakes:

• Using '-eq' instead of '-like' for pattern matching
• Misusing '-match' without if condition
• Using 'contains' which is invalid here