Hash tables (dictionaries) in PowerShell - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this PowerShell hash table access?

Consider the following PowerShell script:

$hash = @{ 'apple' = 3; 'banana' = 5; 'cherry' = 7 }
$result = $hash['banana']
Write-Output $result

What will be printed?

PowerShell

$hash = @{ 'apple' = 3; 'banana' = 5; 'cherry' = 7 }
$result = $hash['banana']
Write-Output $result

A 7

B 3

C 5

D banana

💡 Hint

Think about how to get the value for a key in a hash table.

The hash table stores keys and values. Accessing $hash['banana'] returns the value 5.

📝 Syntax

intermediate

Which option correctly creates a hash table with keys 'x' and 'y' and values 10 and 20?

Choose the correct PowerShell syntax to create a hash table with keys 'x' and 'y' and values 10 and 20 respectively.

A @{ 'x' : 10, 'y' : 20 }

B @{ x = 10; y = 20 }

C @{ 'x' = 10, 'y' = 20 }

D @{ x : 10; y : 20 }

💡 Hint

PowerShell uses = to assign values in hash tables, and semicolons separate pairs.

PowerShell hash tables use @{ key = value; key2 = value2 } syntax. Colons are not used.

🔧 Debug

advanced

Why does this PowerShell hash table script cause an error?

Look at this script:

$hash = @{ 'a' = 1; 'b' = 2 }
Write-Output $hash[a]

Why does it cause an error?

A Because 'a' is not quoted when accessing the hash table key

B Because the hash table keys must be integers

C Because Write-Output cannot print hash table values

D Because the hash table is empty

💡 Hint

Think about how keys are referenced in PowerShell hash tables.

Hash table keys must be quoted strings when accessed by string keys. Without quotes, PowerShell treats 'a' as a variable.

🚀 Application

advanced

How to add a new key-value pair to an existing PowerShell hash table?

You have this hash table:

$hash = @{ 'name' = 'Alice'; 'age' = 30 }

Which command correctly adds a new key 'city' with value 'Seattle'?

A $hash.Add('city', 'Seattle')

B Add-Item $hash 'city' 'Seattle'

C $hash += @{ 'city' = 'Seattle' }

D $hash['city'] = 'Seattle'

💡 Hint

Think about how to assign a new key in a hash table.

Assigning a new key-value pair is done by $hash['key'] = value. The Add() method exists for hashtables but throws an exception if the key already exists.

🧠 Conceptual

expert

What is the count of items in this PowerShell hash table after execution?

Consider this script:

$hash = @{ 'one' = 1; 'two' = 2 }
$hash['three'] = 3
$hash['two'] = 22
$hash.Remove('one')

How many key-value pairs remain in $hash?

A 2

B 3

C 1

D 4

💡 Hint

Count how many keys remain after adding, updating, and removing.

Initially 2 keys. Added 'three' (3 keys). Updated 'two' (still 3 keys). Removed 'one' (2 keys remain).