PowerShell Script to Convert Text to Uppercase

Use the PowerShell method ToUpper() on a string variable like $text.ToUpper() to convert text to uppercase.

Examples

Inputhello world

OutputHELLO WORLD

InputPowerShell 7.3

OutputPOWERSHELL 7.3

Input123abc!@#

Output123ABC!@#

How to Think About It

To convert text to uppercase in PowerShell, you take the original string and apply the built-in ToUpper() method. This method changes all lowercase letters to their uppercase versions while leaving other characters unchanged.

Algorithm

1

Get the input string from the user or a variable

2

Apply the <code>ToUpper()</code> method to the string

3

Store or output the resulting uppercase string

Code

powershell

$text = "hello world"
$uppercaseText = $text.ToUpper()
Write-Output $uppercaseText

Output

HELLO WORLD

Dry Run

Let's trace the input 'hello world' through the code

1

Assign input string

$text = "hello world"

2

Convert to uppercase

$uppercaseText = $text.ToUpper() # Result: "HELLO WORLD"

3

Output result

Write-Output $uppercaseText # Prints: HELLO WORLD

Step	Variable	Value
1	$text	hello world
2	$uppercaseText	HELLO WORLD
3	Output	HELLO WORLD

Why This Works

Step 1: String stored in variable

The original text is stored in a variable $text so it can be manipulated.

Step 2: Use <code>ToUpper()</code> method

Calling ToUpper() on the string converts all lowercase letters to uppercase.

Step 3: Output the uppercase string

The converted uppercase string is printed using Write-Output.

Alternative Approaches

Using pipeline with ForEach-Object

powershell

"hello world" | ForEach-Object { $_.ToUpper() }

This approach works well in pipelines but is less direct for single strings.

Using -replace operator with regex

powershell

"hello world" -replace '[a-z]', { param($c) $c.Value.ToUpper() }

This method is more complex and less efficient but shows regex usage for uppercase conversion.

Complexity: O(n) time, O(n) space

Time Complexity

The ToUpper() method processes each character once, so time grows linearly with string length.

Space Complexity

A new string is created for the uppercase result, so space usage is proportional to input size.

Which Approach is Fastest?

Using ToUpper() directly is the fastest and simplest method compared to pipeline or regex alternatives.

Approach	Time	Space	Best For
Direct ToUpper()	O(n)	O(n)	Simple and fast uppercase conversion
Pipeline with ForEach-Object	O(n)	O(n)	Processing multiple strings in a pipeline
Regex replace with scriptblock	O(n)	O(n)	Complex pattern matching with uppercase conversion