Switch statement in PowerShell

Introduction

A switch statement helps you choose what to do based on different values. It makes your script easier to read when you have many options.

You want to run different code depending on a user's choice.

You need to check a variable against many possible values.

You want to replace many if-else statements with cleaner code.

You want to handle different commands or inputs in a script.

Syntax

PowerShell

switch (<expression>) {
    <value1> { <code1> }
    <value2> { <code2> }
    default { <defaultCode> }
}

The switch keyword starts the statement.

Each value is checked against the expression. If it matches, the code inside runs.

Examples

This example checks the value of $color and prints a message.

PowerShell

switch ($color) {
    'red' { Write-Output 'Stop' }
    'green' { Write-Output 'Go' }
    default { Write-Output 'Wait' }
}

This checks the number 5 and returns 'Five'.

PowerShell

switch (5) {
    1 { 'One' }
    5 { 'Five' }
    default { 'Other' }
}

Sample Program

This script checks the day and prints a message for Tuesday.

PowerShell

$day = 'Tuesday'
switch ($day) {
    'Monday' { Write-Output 'Start of work week' }
    'Tuesday' { Write-Output 'Second day' }
    'Friday' { Write-Output 'Almost weekend' }
    default { Write-Output 'Just another day' }
}

Important Notes

You can use default to catch any value not listed.

Switch statements can match strings, numbers, or even patterns.

Summary

Switch statements help pick actions based on values.

They make code cleaner than many if-else checks.

Use default to handle unexpected cases.

Practice

1. What is the main purpose of a switch statement in PowerShell?

easy

A. To create a variable

B. To repeat a block of code multiple times

C. To define a function

D. To choose one action from many based on a value

Solution

1. Step 1: Understand the role of switch

   A switch statement checks a value and picks the matching case to run.

2. Step 2: Compare with other options

   Loops repeat code, functions define reusable code, variables store data. Only switch picks actions based on value.

3. Final Answer:

   To choose one action from many based on a value -> Option D

4. Quick Check:

   Switch selects action by value = A [OK]

Hint: Switch picks code by matching value, like a menu choice [OK]

Common Mistakes:

• Confusing switch with loops
• Thinking switch defines variables
• Mixing switch with function definition

2. Which of the following is the correct syntax to start a switch statement in PowerShell?

easy

A. switch ($variable) { ... }

B. switch $variable { ... }

C. switch { $variable } ...

D. switch ($variable) then { ... }

Solution

1. Step 1: Recall switch syntax

   PowerShell requires parentheses around the value: switch ($variable) { ... }

2. Step 2: Check other options

   switch $variable { ... } misses parentheses, C has wrong braces, D uses invalid 'then'.

3. Final Answer:

   switch ($variable) { ... } -> Option A

4. Quick Check:

   Parentheses around variable = B [OK]

Hint: Always put the variable inside parentheses after switch [OK]

Common Mistakes:

• Omitting parentheses around the variable
• Using 'then' keyword incorrectly
• Wrong brace placement

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

switch (3) {
  1 { 'One' }
  2 { 'Two' }
  3 { 'Three' }
  default { 'Other' }
}

medium

A. Three

B. Two

C. Other

D. One

Solution

1. Step 1: Identify the switch value

   The switch is checking the value 3.

2. Step 2: Match the case

   Case 3 matches and outputs 'Three'. Default is ignored because a match was found.

3. Final Answer:

   Three -> Option A

4. Quick Check:

   Value 3 matches case 3 = D [OK]

Hint: Match value to case; default runs only if no match [OK]

Common Mistakes:

• Choosing default even when a case matches
• Confusing case numbers
• Ignoring case order

4. Identify the error in this PowerShell switch statement:

switch $color {
  'red' { 'Stop' }
  'green' { 'Go' }
  default { 'Wait' }
}

medium

A. Missing quotes around case values

B. Missing parentheses around $color

C. Missing default case

D. Incorrect use of curly braces

Solution

1. Step 1: Check switch syntax

   PowerShell requires parentheses around the variable in switch: switch ($color) { ... }

2. Step 2: Verify other parts

   Quotes around case values and default case are correct; curly braces are used properly.

3. Final Answer:

   Missing parentheses around $color -> Option B

4. Quick Check:

   Parentheses required around variable = A [OK]

Hint: Always wrap the switch variable in parentheses [OK]

Common Mistakes:

• Omitting parentheses around the switch variable
• Thinking quotes are optional for strings
• Confusing default case necessity

5. You want to write a switch statement that prints 'Weekend' for Saturday and Sunday, 'Weekday' for Monday to Friday, and 'Invalid' for any other input. Which code snippet correctly implements this?

hard

A. switch ($day) { 'Saturday' { 'Weekend' } 'Sunday' { 'Weekend' } 'Monday','Tuesday','Wednesday','Thursday','Friday' { 'Weekday' } default { 'Invalid' } }

B. switch ($day) { 'Saturday' -or 'Sunday' { 'Weekend' } 'Monday' -or 'Tuesday' -or 'Wednesday' -or 'Thursday' -or 'Friday' { 'Weekday' } default { 'Invalid' } }

C. switch ($day) { 'Saturday' { 'Weekend' } 'Sunday' { 'Weekend' } 'Monday' { 'Weekday' } 'Tuesday' { 'Weekday' } 'Wednesday' { 'Weekday' } 'Thursday' { 'Weekday' } 'Friday' { 'Weekday' } default { 'Invalid' } }

D. switch ($day) { 'Saturday','Sunday' { 'Weekend' } 'Monday','Tuesday','Wednesday','Thursday','Friday' { 'Weekday' } default { 'Invalid' } }

Solution

1. Step 1: Recall PowerShell switch case syntax

   Each case must have exactly one pattern followed by { action }. Multiple values require separate case statements.

2. Step 2: Check each option

   A lists a separate case for each day: correct syntax and produces expected output.
   B uses -or which evaluates to $true (boolean) and won't match string days.
   C and D use commas to attempt grouping, but this causes syntax errors (unexpected token ',').

3. Final Answer:

   switch ($day) { 'Saturday' { 'Weekend' } 'Sunday' { 'Weekend' } 'Monday' { 'Weekday' } 'Tuesday' { 'Weekday' } 'Wednesday' { 'Weekday' } 'Thursday' { 'Weekday' } 'Friday' { 'Weekday' } default { 'Invalid' } } -> Option C

4. Quick Check:

   Separate cases per value, no commas in patterns = A [OK]

Hint: Use separate case statements for multiple matching values [OK]

Common Mistakes:

• Using '-or' inside switch case labels
• Trying to group values with commas (syntax error)
• Incorrectly assuming comma grouping works like other languages