Arrays in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this PowerShell array operation?

Consider the following PowerShell code snippet. What will be the output after running it?

PowerShell

$arr = 1,2,3,4,5
$arr[1..3]

A 2 3 4

B 3 4 5

C 1 2 3

D 1 3 5

💡 Hint

Remember that array slicing with [start..end] includes both start and end indices.

The slice $arr[1..3] selects elements at indices 1, 2, and 3, which are 2, 3, and 4 respectively.

📝 Syntax

intermediate

Which option correctly creates an array of strings in PowerShell?

Select the option that correctly creates an array containing the strings "apple", "banana", and "cherry".

A $fruits = {'apple', 'banana', 'cherry'}

B $fruits = ['apple', 'banana', 'cherry']

C $fruits = @('apple', 'banana', 'cherry')

D $fruits = array('apple', 'banana', 'cherry')

💡 Hint

PowerShell uses @() to create arrays.

Option C uses the correct syntax @() to create an array. Options B, C, and D are invalid in PowerShell for array creation.

🔧 Debug

advanced

Why does this PowerShell array code produce an error?

The following code is intended to add an element to an existing array, but it causes an error. What is the reason?

PowerShell

$arr = 1,2,3
$arr += 4
$arr[3]

A Error because arrays in PowerShell are fixed size and cannot be appended

B No error occurs; output is 4

C Error because += operator is not valid for arrays

D Error because $arr[3] is out of range

💡 Hint

Try running the code in PowerShell to see the actual behavior.

In PowerShell, += on arrays creates a new array with the added element. So $arr becomes 1,2,3,4 and $arr[3] is 4.

🚀 Application

advanced

How to filter an array to only even numbers in PowerShell?

Given an array $numbers = 1..10, which option correctly filters it to only even numbers?

PowerShell

$numbers = 1..10

A $even = $numbers | Where-Object { $_ % 2 -eq 0 }

B $even = $numbers.Where({ $_ % 2 -eq 0 })

C $even = $numbers | Filter { $_ % 2 -eq 0 }

D $even = $numbers | Select-Object { $_ % 2 -eq 0 }

💡 Hint

Use the correct cmdlet for filtering in PowerShell pipelines.

Where-Object is the correct cmdlet to filter elements in a pipeline. Options A, B, and D are invalid or incorrect usage.

🧠 Conceptual

expert

What is the length of the array after this PowerShell operation?

Given the code below, what is the length of $arr after execution?

PowerShell

$arr = 1,2,3
$arr = $arr + @(4,5)
$arr = $arr[1..3]

A 2

B 5

C 4

D 3

💡 Hint

Track the array length after each operation carefully.

Initially $arr has 3 elements. After adding @(4,5), it has 5 elements. Then slicing [1..3] selects 3 elements, so length is 3.