arrays.md

Arrays

Arrays are immutable. There are three types - default, strongly typed, and ArrayList

Create a Default Array

Type: [PSObject[]]. Holds any type of data value.

$arr = @("cats", "dogs", "parrots")

Even easier, is to skip the @ sign:

$arr = ("cats", "dogs", "parrots")

Or, long-hand is to define what type of array it is:

[PSObject[]] $kitchen = 'apples', 'silverware', 18

List its contents

$arr

Prints items in the array like so:

cats
dogs
parrots

Number of objects in the array - called arr - is 3:

$arr|Measure-Object  

Or, simply use .count, which is within Measure-Object:

$arr.count 

Array Operators

Check for whether something exists in the array

$arr -contains <item to look for>

Returns a boolean.

Smush the objects together

Original array is unchanged; output is a single object, whose itmes are separated by what you tell them to be joined by.

Return a single object with spaces and commas between the strings ("cats, dogs, parrots")

$arr -join ", "

Prove this with:

$arr -join ", "|Measure-Object  

Return the object that you're looking for

Checks for equality, but unlike contains, will return the item if it exists.

$arr -eq "parrot"

If the object doesn't exist, it won't return a thing.

Use ne to return the items that are not equal to what you're looking for.

Combine Arrays with "Concatenate" and "Plus Equals"

My sample arrays:

$animals = ('cats', 'dogs', 'horses')
$dolphins = ('bottlenose', 'white-sided')

Concatenate arrays

The second array is appended to the first.

Six objects are printed out:

$animals+$dolphins

Plus Equals

The += command copies the values from the array and makes a brand new array, that includes the old and the new value(s):

Add "mice" to the animals array:

$animals+= 'mice'

Add the dolphins array to the animals array (keeps the original dolphin array but deletes and replaces the original animals array):

$animals+= $dolphins

Note that the old array is deleted.

Strongly Typed Arrays

Available for using when you only want a specific data type in the array.

For example, integers only:

[int[]] $ages = 4, 36, 47

Or, strings only:

[string[]] $flowers = "daffodil", "roses", "bleeding heart"

ArrayLists

A collection - uses the .Net framework. May not be used as much in more complex code.

ArrayObjects

Make an array of objects.

This uses the @() function.

$shoes = @(
[pscustomobject]@{Color='blue'; Type='boots'}
[pscustomobject]@{Color='brown'; Type='heels'}
[pscustomobject]@{Color='black'; Type='neoprene booties'}
)

When you access the array of objects, with $shoes, you get:

Color Type
----- ----
blue  boots
brown heels
black neoprene booties

Get a property

To access only a particular property of an object in the array, such as "heels:"

$shoes[1].Type

Update a property

Update the "Type" from "heels" to "sandals:"

$shoes[1].Type = 'sandals'

Get all the properties in the array of objects

Iterate through in a PowerShell friendly way:

$shoes.Type

Resources

• Varonis Powershell Blog