PowerShell Script to Find Average of Array

Use $average = ($array | Measure-Object -Average).Average to find the average of an array in PowerShell.

Examples

Input[1, 2, 3, 4, 5]

Output3

Input[10, 20, 30]

Output20

Input[]

Output0

How to Think About It

To find the average, sum all numbers in the array and then divide by how many numbers there are. PowerShell's Measure-Object cmdlet can do this easily by calculating the average directly.

Algorithm

1

Get the array of numbers.

2

Use a built-in command to calculate the average of the array.

3

Store the result in a variable.

4

Print or return the average.

Code

powershell

$array = @(1, 2, 3, 4, 5)
$average = ($array | Measure-Object -Average).Average
if ($null -eq $average) { $average = 0 }
Write-Output "Average is $average"

Output

Average is 3

Dry Run

Let's trace the array [1, 2, 3, 4, 5] through the code

1

Define array

$array = @(1, 2, 3, 4, 5)

2

Calculate average

$average = (1+2+3+4+5)/5 = 15/5 = 3

3

Output result

Print 'Average is 3'

Iteration	Value	Running Sum
1	1	1
2	2	3
3	3	6
4	4	10
5	5	15

Why This Works

Step 1: Using Measure-Object

The Measure-Object -Average cmdlet calculates the average of numbers piped into it.

Step 2: Handling empty arrays

If the array is empty, Measure-Object returns $null, so we set average to 0 to avoid errors.

Step 3: Output the result

We use Write-Output to display the average in a readable format.

Alternative Approaches

Manual sum and count

powershell

$array = @(1, 2, 3, 4, 5)
$sum = 0
foreach ($num in $array) { $sum += $num }
$count = $array.Count
$average = if ($count -gt 0) { $sum / $count } else { 0 }
Write-Output "Average is $average"

This method manually sums and counts elements; it's more verbose but shows the calculation steps explicitly.

Using LINQ-like method with .NET

powershell

$array = @(1, 2, 3, 4, 5)
$average = [System.Linq.Enumerable]::Average($array)
Write-Output "Average is $average"

Uses .NET's LINQ Average method; requires the array to be compatible and may be less familiar to beginners.

Complexity: O(n) time, O(1) space

Time Complexity

Calculating the average requires visiting each element once to sum values, so it is O(n) where n is the number of elements.

Space Complexity

The calculation uses a fixed amount of extra space regardless of input size, so it is O(1).

Which Approach is Fastest?

Using Measure-Object is efficient and concise; manual summing is similar in speed but more verbose; .NET LINQ may add overhead.

Approach	Time	Space	Best For
Measure-Object -Average	O(n)	O(1)	Quick and simple scripts
Manual sum and count	O(n)	O(1)	Learning and explicit control
.NET LINQ Average	O(n)	O(1)	When using .NET methods or complex queries