Parameters in PowerShell - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a parameter named 'Name'.

PowerShell

param([string]$[1])
Write-Output "Hello, $Name!"

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

Aparam

BNameParam

CName

DInputName

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different name than the variable used in the script.

Forgetting to put the parameter inside the param() block.

The 'param' block defines parameters. Inside it, you list parameter names. Here, 'Name' is the parameter.

2fill in blank

medium

Complete the code to make the parameter 'Age' mandatory.

PowerShell

param(
    [Parameter([1]=$true)]
    [int]$Age
)
Write-Output "Age is $Age"

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

AMandatory

BRequired

CForce

DNeeded

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Required' instead of 'Mandatory'.

Not using the Parameter attribute at all.

The 'Mandatory' attribute makes a parameter required in PowerShell.

3fill in blank

hard

Fix the error in the parameter declaration to accept multiple strings.

PowerShell

param(
    [string[]]$[1]
)
Write-Output "Items: $($Items -join ', ')"

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

AList

BItem

CItemList

DItems

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different parameter name than the variable used in the script.

Forgetting the array type [string[]].

The variable used later is $Items, so the parameter name must be 'Items'.

4fill in blank

hard

Fill both blanks to define a parameter 'Count' with a default value of 5.

PowerShell

param(
    [int]$[1] = [2]
)
Write-Output "Count is $Count"

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

ACount

B10

C5

DNumber

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different parameter name than the variable used.

Setting the wrong default value.

The parameter name is 'Count' and the default value is 5.

5fill in blank

hard

Fill all three blanks to create a parameter 'Verbose' that is a switch and mandatory.

PowerShell

param(
    [Parameter([1]=$true)]
    [[2]]$[3]
)
if ($Verbose) { Write-Output "Verbose mode on" }

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

AMandatory

BSwitch

CVerbose

DBoolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using Boolean instead of Switch for flags.

Not making the parameter mandatory when required.

The parameter is mandatory, of type Switch, and named Verbose.

Practice

1. What is the purpose of using param() in a PowerShell script?

easy

A. To declare input parameters that the script can accept

B. To define a function inside the script

C. To output results from the script

D. To comment lines in the script

Solution

1. Step 1: Understand the role of param()

   The param() block is used at the start of a PowerShell script to declare parameters that the script can accept as input.

2. Step 2: Differentiate from other script parts

   It is not used to define functions, output results, or comment lines. Those have different syntax and purposes.

3. Final Answer:

   To declare input parameters that the script can accept -> Option A

4. Quick Check:

   param() declares input parameters [OK]

Hint: Remember: param() is for input, not output or comments [OK]

Common Mistakes:

• Confusing param() with function declaration
• Thinking param() outputs data
• Using param() to comment code

2. Which of the following is the correct syntax to declare a mandatory string parameter named Name in PowerShell?

easy

A. param([string]$Name = "")

B. param([string]$Name)

C. param($Name:string Mandatory)

D. param([Parameter(Mandatory=$true)][string]$Name)

Solution

1. Step 1: Understand mandatory parameter syntax

   To make a parameter mandatory, use the [Parameter(Mandatory=$true)] attribute before the type and name.

2. Step 2: Check each option

   param([Parameter(Mandatory=$true)][string]$Name) correctly uses [Parameter(Mandatory=$true)][string]$Name. param([string]$Name = "") sets a default empty string, so not mandatory. param([string]$Name) lacks the mandatory attribute. param($Name:string Mandatory) is invalid syntax.

3. Final Answer:

   param([Parameter(Mandatory=$true)][string]$Name) -> Option D

4. Quick Check:

   Mandatory parameter needs [Parameter(Mandatory=$true)] [OK]

Hint: Mandatory parameters use [Parameter(Mandatory=$true)] attribute [OK]

Common Mistakes:

• Omitting the Mandatory attribute
• Using default value instead of mandatory
• Incorrect attribute syntax

3. What will be the output of this script when run with -Count 3?

param([int]$Count = 1)
for ($i = 1; $i -le $Count; $i++) { Write-Output "Number $i" }

medium

A. Number 1
Number 2
Number 3

B. Number 1

C. Number 3

D. Error: Missing parameter

Solution

1. Step 1: Understand parameter default and input

   The parameter $Count has a default of 1 but is overridden by passing -Count 3.

2. Step 2: Trace the loop output

   The for loop runs from 1 to 3, outputting "Number 1", "Number 2", and "Number 3" each on a new line.

3. Final Answer:

   Number 1 Number 2 Number 3 -> Option A

4. Quick Check:

   Loop runs 3 times with Count=3 [OK]

Hint: Parameter overrides default; loop runs Count times [OK]

Common Mistakes:

• Ignoring passed parameter and using default
• Expecting single output instead of looped output
• Confusing parameter name or type

4. Identify the error in this parameter declaration:

param([int]$Age = "twenty")

medium

A. Missing mandatory attribute

B. Type mismatch: assigning string to int parameter

C. Parameter name cannot be Age

D. Default value must be null

Solution

1. Step 1: Check parameter type and default value

   The parameter $Age is declared as [int] but the default value is the string "twenty".

2. Step 2: Understand type mismatch error

   PowerShell cannot convert the string "twenty" to an integer, causing a type mismatch error.

3. Final Answer:

   Type mismatch: assigning string to int parameter -> Option B

4. Quick Check:

   Default value must match parameter type [OK]

Hint: Default values must match declared parameter type [OK]

Common Mistakes:

• Assigning string default to int parameter
• Ignoring type mismatch errors
• Assuming parameter name restrictions

5. You want to create a script that accepts two parameters: Path (string, mandatory) and Verbose (switch, optional). Which is the correct way to declare these parameters?

hard

A. param([string]$Path, [Parameter(Mandatory=$true)][switch]$Verbose)

B. param([string]$Path = "", [switch]$Verbose = $false)

C. param([Parameter(Mandatory=$true)][string]$Path, [switch]$Verbose)

D. param([switch]$Path, [string]$Verbose)

Solution

1. Step 1: Identify mandatory and optional parameters

   Path must be mandatory string, so use [Parameter(Mandatory=$true)][string]$Path. Verbose is an optional switch, so [switch]$Verbose without mandatory attribute.

2. Step 2: Evaluate each option

   param([Parameter(Mandatory=$true)][string]$Path, [switch]$Verbose) correctly declares Path as mandatory string and Verbose as optional switch. param([string]$Path, [Parameter(Mandatory=$true)][switch]$Verbose) wrongly makes Verbose mandatory. param([string]$Path = "", [switch]$Verbose = $false) sets default empty string for Path, so not mandatory. param([switch]$Path, [string]$Verbose) swaps types incorrectly.

3. Final Answer:

   param([Parameter(Mandatory=$true)][string]$Path, [switch]$Verbose) -> Option C

4. Quick Check:

   Mandatory string + optional switch = param([Parameter(Mandatory=$true)][string]$Path, [switch]$Verbose) [OK]

Hint: Mandatory uses [Parameter(Mandatory=$true)], switches don't [OK]

Common Mistakes:

• Making switches mandatory
• Setting default values instead of mandatory
• Mixing parameter types