PowerShell Script to Find Largest Number in Array

Use $array | Measure-Object -Maximum to find the largest number in an array, for example: ($array | Measure-Object -Maximum).Maximum returns the largest value.

Examples

Input[3, 5, 1, 9, 2]

Output9

Input[10, 10, 10]

Output10

Input[-5, -1, -10]

Output-1

How to Think About It

To find the largest number in an array, look at each number and keep track of the biggest one you have seen so far. At the end, the biggest number you kept is the largest in the array.

Algorithm

1

Get the array of numbers.

2

Start with the first number as the largest.

3

Compare each number in the array to the current largest.

4

If a number is bigger, update the largest number.

5

After checking all numbers, return the largest number.

Code

powershell

$array = @(3, 5, 1, 9, 2)
$largest = ($array | Measure-Object -Maximum).Maximum
Write-Output "Largest number is $largest"

Output

Largest number is 9

Dry Run

Let's trace the array [3, 5, 1, 9, 2] through the code

1

Input array

The array is 3, 5, 1, 9, 2

2

Measure-Object finds maximum

It compares all numbers and finds 9 as the largest

3

Output result

Prints 'Largest number is 9'

Number	Current Largest
3	3
5	5
1	5
9	9
2	9

Why This Works

Step 1: Using Measure-Object

The Measure-Object -Maximum command scans the array and finds the highest number.

Step 2: Extracting the Maximum

The property .Maximum holds the largest value found by Measure-Object.

Step 3: Output the result

We use Write-Output to print the largest number in a readable format.

Alternative Approaches

Using a loop to find largest

powershell

$array = @(3, 5, 1, 9, 2)
$largest = $array[0]
foreach ($num in $array) {
  if ($num -gt $largest) { $largest = $num }
}
Write-Output "Largest number is $largest"

This method manually compares each number and is easy to understand but longer than Measure-Object.

Using Sort-Object

powershell

$array = @(3, 5, 1, 9, 2)
$largest = $array | Sort-Object -Descending | Select-Object -First 1
Write-Output "Largest number is $largest"

Sorting the array and picking the first element works but is less efficient for large arrays.

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

Time Complexity

The script checks each element once, so time grows linearly with array size.

Space Complexity

No extra space is needed besides a few variables, so space is constant.

Which Approach is Fastest?

Using Measure-Object is efficient and concise; manual loops are clear but longer; sorting is slower due to extra operations.

Approach	Time	Space	Best For
Measure-Object -Maximum	O(n)	O(1)	Quick and clean for any array size
Manual loop	O(n)	O(1)	Clear logic for beginners
Sort-Object then select	O(n log n)	O(n)	When sorted array is also needed