Understanding Arrays in PowerShell

What is an Array?

An array in PowerShell is a collection of items stored in a single variable. Each item, or element, can be of any type: strings, integers, objects, or even other arrays. Unlike some other languages, PowerShell arrays are heterogeneous, meaning they can store different types of elements within the same array.

# Example of a heterogeneous array
$array = @("String", 123, $true, (Get-Date))
$array

# Output
String
123
True

Wednesday, 4 December 2024 09:23:04

Creating Arrays

# Initialize an empty array
$emptyArray = @()

# Array with elements
$numbers = @(1, 2, 3, 4, 5)

Array Assignment Without @()

PowerShell automatically treats comma-separated values as an array.

$numbers = 1, 2, 3, 4, 5

Accessing and Manipulating Arrays

Each element in an array is accessed by its index, starting from zero.

# Accessing elements
$firstElement = $numbers[0]
$lastElement = $numbers[-1]  # Negative indexing accesses from the end

# Modify an element
$numbers[1] = 10

# Add elements
$numbers += 6

Removing Elements

PowerShell lacks a direct Remove() method for arrays, but you can filter out elements using a pipeline.

# Remove an element
$numbers = $numbers | Where-Object { $_ -ne 10 }

Array Methods and Properties

Arrays in PowerShell have several methods and properties inherited from the .NET framework.

Count Property

Get the number of elements in an array.

$numbers.Count

Contains() Method

Check if an array contains a specific value.

$numbers.Contains(5)

Sort and Reverse Arrays

Manipulate the order of elements.

# Sort
$sortedArray = $numbers | Sort-Object

# Reverse
$reversedArray = $numbers | ForEach-Object { $_ } | Sort-Object -Descending

Multidimensional and Jagged Arrays

A multidimensional array is a grid-like structure.

# Create a 2x2 array - Multidimensional
$matrix = @(@(1, 2), @(3, 4))
$matrix[0][1]  # Access second element of the first array

# Jagged array - arrays of arrays with varying lengths
$jagged = @(@(1, 2), @(3, 4, 5))