PowerShell Script to Reverse a String Easily

Use -join ($string.ToCharArray()[-1..-($string.Length)]) to reverse a string in PowerShell, for example: $reversed = -join ($string.ToCharArray()[-1..-($string.Length)]).

Examples

Inputhello

Outputolleh

InputPowerShell

OutputllehSrewoP

Input

Output

How to Think About It

To reverse a string, think of it as flipping the order of its characters. You can convert the string into an array of characters, then read that array backward and join the characters back into a string.

Algorithm

1

Get the input string.

2

Convert the string into an array of characters.

3

Reverse the order of the characters in the array.

4

Join the reversed characters back into a single string.

5

Return or print the reversed string.

Code

powershell

$string = "PowerShell"
$reversed = -join ($string.ToCharArray()[-1..-($string.Length)])
Write-Output $reversed

Output

llehSrewoP

Dry Run

Let's trace reversing the string 'hello' through the code

1

Convert string to array

'hello' becomes ['h','e','l','l','o']

2

Reverse array using index range

Select characters from last to first: ['o','l','l','e','h']

3

Join reversed array

Join characters to form 'olleh'

Index	Character
4	o
3	l
2	l
1	e
0	h

Why This Works

Step 1: Convert string to array

Using ToCharArray() splits the string into individual characters so we can reorder them.

Step 2: Reverse the array

Using the index range [-1..-($string.Length)] selects characters from the end to the start.

Step 3: Join characters

The -join operator combines the reversed characters back into a single string.

Alternative Approaches

Using [array]::Reverse()

powershell

$array = $string.ToCharArray()
[array]::Reverse($array)
$reversed = -join $array
Write-Output $reversed

This method modifies the array in place and is clear but requires extra steps.

Using a for loop

powershell

$reversed = ""
for ($i = $string.Length - 1; $i -ge 0; $i--) { $reversed += $string[$i] }
Write-Output $reversed

This manual approach is easy to understand but less efficient for long strings.

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

Time Complexity

Reversing requires visiting each character once, so time grows linearly with string length.

Space Complexity

An extra array of characters is created, so space also grows linearly with string length.

Which Approach is Fastest?

Using -join with a reversed array is concise and efficient; the in-place [array]::Reverse() is similar but requires more lines.

Approach	Time	Space	Best For
-join with reversed range	O(n)	O(n)	Concise and readable
[array]::Reverse()	O(n)	O(n)	In-place array reversal
For loop concatenation	O(n^2)	O(n)	Simple logic but slower for long strings